: :

ISBN 978-5-93286-157-8

9 785932 861578

Python Essential Reference

Fourth Edition

David Beazley

Python

- 2010

High tech

Python.

.

. . . . . . .

.

Python. . . . .: -, 2010. 864 ., .

ISBN 978-5-93286-157-8

Python. - Python. - ; , . , Python. - , , - .

Python, , , , . , - , , .

- , . - , Python 2.6 Python 3.

ISBN 978-5-93286-157-8 ISBN 978-0-672-32978-4 ()

-, 2010Authorized translation of the English edition 2009 Pearson Education, Inc. This trans lation is pub lished and sold by permission of Pearson Education, Inc., the owner of all rights to publish and sell the same.

, - . -, , .

-. 199034, -, 16 , 7,. (812) 324-5353, www.symbol.ru. N 000054 25.12.98.

30.07.2010. 70100 1/16. . 54 . . 1200 .

199034, -, 9 , 12.

, .

...............................................................................15

........................................................................17

................................................................................19

I. Python ..........................................21

1. ...........................................................23 ...........................................................23

..............................25

.............................................................28

- ..........................................29

................................................................................30

................................................................................32

..............................................................................33

...........................................................................35

...............................................................................36

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.............................................................................39

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...............................................................47

2. ...........................48 .....................................................48

...........................49

..............................................................50

.............................................................51

.........................................................................54

, ......................54

.....................................................55

.........................................................................55

..................................56

8

3. .......................................................57 ......................................................................57

...................................................58

.............................................59

....................................................................60

........................................................61

.................................63

.........................................75

............................80

..............................84

4. .....................................................96 ..........................................................96

.......................................99

........................................................ 103

..................... 105

...................................................... 108

................................................. 109

........................... 109

(.) ........................................... 110

() ................................................. 110

.................................................... 111

...................... 112

....................................... 113

........................................................... 113

.......................................................... 114

5. ... 116 .................................. 116

....................................................... 117

.............................................................. 117

...................................................................... 120

with .............................. 126

__debug__ ....................... 128

6. ............... 130 ........................................................................... 130

...................... 133

............................................................. 134

...................................... 136

....................................................................... 139

yield ............................................. 141

yield ........................................... 143

9

.............................. 146

............................................................ 148

- ....................................................... 150

........................................ 151

lambda ................................................................. 152

........................................................................... 153

................................................... 154

............................................................. 155

eval(), exec() compile() .......................................... 156

7. - .... 158 class ................................................................ 158

............................................................. 159

............................................................. 160

..................................................................... 160

, .................................................. 165

................................... 165

............................................................................ 167

...................................................................... 170

............................ 171

.............................................. 172

.................... 176

__slots__ ........................................................................... 177

........................................................ 178

............................ 180

................................................ 182

....................................................................... 184

8. , ........................................ 189 import ................................................ 189

......................... 191

.............. 193

........................................................... 194

........................................... 195

................................ 196

.............................................................................. 197

Python ......... 200

........................................... 203

9. ..................................................................... 205 ................................... 205

...................................................... 207

..................................................... 207

, ......... 211

10

print ............................................................... 212

print() .................................................................. 213

........................ 213

.............................................. 214

.................................................... 215

- ........................................................... 218

pickle ..................................... 223

10. ........................................................... 226 ............................... 226

........................................................ 229

Python ..................................... 230

.................. 231

........................... 232

........................................ 232

....................................................... 234

11. , , .. 236 doctest ............................ 236

unittest ............................. 239

Python pdb .............................................. 242

................................................ 247

.................................................... 248

II. Python ........................................ 257

12. ........................................................ 259 ................................................ 259

...................................................... 273

................................................ 278

future_builtins ........................................................ 279

13. Python ................................ 280 atexit ..................................................................... 280

copy ....................................................................... 280

gc .......................................................................... 281

inspect ................................................................... 283

marshal .................................................................. 288

pickle ..................................................................... 289

sys ......................................................................... 292

traceback ................................................................ 300

types ...................................................................... 301

warnings ................................................................. 303

weakref .................................................................. 305

11

14. ..................................................................... 309 decimal ................................................................... 309

fractions ................................................................. 317

math ...................................................................... 319

numbers ................................................................. 321

random ................................................................... 322

15. , .......................................... 326

abc ......................................................................... 326

array ...................................................................... 328

bisect ..................................................................... 331

collections ............................................................... 332

contextlib ............................................................... 339

functools ................................................................ 339

heapq ..................................................................... 341

itertools .................................................................. 342

operator .................................................................. 346

16. ............................................. 349 codecs .................................................................... 349

re .......................................................................... 354

string ..................................................................... 362

struct ..................................................................... 366

unicodedata ............................................................. 369

17. ..................................................... 375 ... 375

sqlite3 .................................................................... 383

DBM ............................. 391

shelve ..................................................................... 393

18. ........................................ 395 bz2 ........................................................................ 395

filecmp ................................................................... 396

fnmatch .................................................................. 398

glob ....................................................................... 399

gzip ....................................................................... 400

shutil ..................................................................... 400

tarfile .................................................................... 402

tempfile .................................................................. 407

zipfile .................................................................... 409

zlib ........................................................................ 413

19. ....................................... 415 commands ............................................................... 416

ConfigParser configparser ....................................... 416

12

datetime ................................................................. 421

errno ...................................................................... 430

fcntl ....................................................................... 434

io ........................................................................... 437

logging ................................................................... 445

mmap .................................................................... 463

msvcrt .................................................................... 467

optparse ................................................................. 469

os .......................................................................... 475

os.path ................................................................... 496

signal ..................................................................... 499

subprocess ............................................................... 503

time ....................................................................... 507

winreg .................................................................... 511

20. ............................................... 516 .............................................................. 516

Python ............................ 518

multiprocessing ....................................................... 519

threading ................................................................ 545

queue (Queue) .......................................................... 556

............................................... 559

21. .................................................... 561 ............................... 561

asynchat ................................................................. 564

asyncore ................................................................. 568

select ..................................................................... 572

socket ..................................................................... 586

ssl.......................................................................... 608

SocketServer ........................................................... 611

22. - ................................... 619 ftplib ..................................................................... 619

http ......................................................................... 623

smtplib ................................................................... 639

urllib ........................................................................ 640

xmlrpc ...................................................................... 651

23. - ................................................... 660 cgi ......................................................................... 662

cgitb ...................................................................... 670

WSGI ................................................................ 671

wsgiref ..................................................................... 673

13

24. .............. 677 base64 .................................................................... 677

binascii ................................................................... 680

csv ......................................................................... 681

email ........................................................................ 685

hashlib ................................................................... 694

hmac ...................................................................... 695

HTMLParser ........................................................... 696

json ....................................................................... 699

mimetypes .............................................................. 703

quopri .................................................................... 704

xml .......................................................................... 706

25. .................................... 725 Python ............................................ 725

................................................................. 726

............ 727

.................................................................................. 727

...................... 728

........................................................ 728

.................................................... 728

.............................................................. 729

III. ............................................... 731

26. Python ........... 733 ........................................................... 734

Python ..................................... 754

ctypes..................................................................... 759

.................................................. 768

Jython IronPython ............................................................ 769

A. Python 3 ........................................................ 770 Python 3? ...................................... 770

................................................... 771

.............................................................. 780

2to3 ............................ 788

......................................................... 794

. (David M. Beazley) Python, 1996 . , , - SWIG, - , C/C++, -, Python, Perl, Ruby, Tcl Java. - , PLY, - lex1 yacc2 Python. - - Python - . , . , , , , Python -. http://www.dabeaz.com.

1 . . .

2 . . .

(Noah Gift) Python For UNIX and Linux System Administration ( OReilly).1 - Google App Engine In Action ( Manning). , , -. , IBM developerWorks, Red Hat Magazine, OReilly MacTech. - http://www.giftcs.com, , http://noahgift.com. , - Twitter.

- , -, - , . Apple LPI. , Caltech, Disney Feature Animation, Sony Imageworks Turner Studios. Weta Digital, . , , - .

1 . , . Python UNIX Linux. . . .: -, 2009.

. , , . (Kurt Grandis) - . (Timothy Boronczyk), (Paul DuBois), (Mats Wichmann), (David Ascher) (Tim Bell) , . (Guido van Rossum), - (Jeremy Hylton), (Fred Drake), (Roger Masse) (Barry Warsaw) - , 1999 . , , . , , , . - Addison-Wesley Pearson Education . (Mark Taber), (Michael Thurston), (Seth Kerney) (Lisa Thibault) , - . (Robin Drake), . , - , .

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: Mark Taber Associate Publisher Pearson Education 800 East 96th Street Indianapolis, IN 46240 USA

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- Python. -Python. -. - Python , -Python , - , - . , - Python Python. , Python , C Java. , -C Java. , - Java. , -Java. , -. , - (, ) .

Python http://www.python.org. , UNIX, Windows Macintosh. , - Python , - .

Python. -Python. -. - Python 2.6 Py-Python 2.6 Py- 2.6 Py-Py-thon 3.0. Python 3 - 3.0. Python 3 -Python 3 - 3 - . : Python 3.0 -Python 3.0 - 3.0 - Python 2.x, ?

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Python . -Python . - . - python. - - (, Jython, IronPython, IDLE, ActivePython, Wing IDE, pydev ), . - , - , -. -, , - >>>, , :

24 1.

Python 2.6rc2 (r26rc2:66504, Sep 19 2008, 08:50:24)

[GCC 4.0.1 (Apple Inc. build 5465)] on darwin

Type help, copyright, credits or license for more information.

>>> print ,

,

>>>

SyntaxError, , Py-Py-thon 3. - , , print Python 3 -Python 3 - 3 - . , . :

>>> print(, )

,

>>>

Python 2, -Python 2, - 2, -, . Python. , - , , , Python 2 Python 3.

Python . - . , , - Python . :

>>> 6000 + 4523.50 + 134.12

10657.620000000001

>>> _ + 8192.32

18849.940000000002

>>>

Python -Python - - _, - . . , - .

, , , :

# helloworld.py

print ,

25

Python -Python - - .py. # - , .

helloworld.py, , :

% python helloworld.py

,

%

Python Windows, .py (Run command), (Start). -, . , - ( , ). - Python, IDLE.

UNIX #!, :

#!/usr/bin/env python

print ,

, . - EOF (end of file ) Exit () Python. UNIX EOF Ctrl+D; Windows Ctrl+Z. - , SystemExit.

>>> raise SystemExit

1.1 , .

1.1.

principal = 1000 #

rate = 0.05 #

numyears = 5 #

year = 1

while year

26 1.

1 1050.0

2 1102.5

3 1157.625

4 1215.50625

5 1276.2815625

Python , . - . -, , . Python C, , , , . Python 1.1 principal. . - :

principal = principal * (1 + rate)

- principal. - principal 1000, ( rate - , ). principal . , , , principal, , .

. - , , :

principal = 1000; rate = 0.05; numyears = 5;

while , . , while. , -, , . , 1.1 - , while. Python , , - . ( ).

, 1.1, - .

27

, principal . - . - (%), :

print %3d %0.2f % (year, principal)

print(%3d %0.2f % (year, principal)) # Python 3

, :

1 1050.00

2 1102.50

3 1157.63

4 1215.51

5 1276.28

, %d, %s %f. - , . - , - . , %3d , - 3 , %0.2f , . - printf() C - 4 .

- , format(). :

print format(year,3d),format(principal,0.2f)

print(format(year,3d),format(principal,0.2f)) # Python 3

format() , (%). -, 3d , - 3 , 0.2f , . , for-mat(), - . :

print {0:3d} {1:0.2f}.format(year,principal)

print({0:3d} {1:0.2f}.format(year,principal)) # Python 3

{0:3d} {1:0.2f} format(), .

28 1.

if else. -:

if a < b:

print

else:

print

if else . else - .

, , - pass, :

if a < b:

pass #

else:

print

or, and not:

if product == and type == \

and not (age < 4 or age > 8):

print !

. , - , (\) , . - , , - , .

Python , switch case. - , elif, :

if suffix == .htm:

content = text/html

elif suffix == .jpg:

content = image/jpeg

elif suffix == .png:

content = image/png

else:

raise RuntimeError( )

True False Boolean. :

if spam in s:

has_spam = True

- 29

else:

has_spam = False

, < >, True False. - in, , , -, . True False, - , :

has_spam = spam in s

- :

f = open(foo.txt) #

line = f.readline() # readline()

while line:

print line, # ,

# print(line,end=) # Python 3

line = f.readline()

f.close()

open() . , . read-line() , . .

foo.txt. , - (, , , - ), . , Python for, - . , - :

for line in open(foo.txt):

print line,

, print - >> , :

f = open(out,w) #

while year >f,%3d %0.2f % (year,principal)

year += 1

f.close()

>> Python 2. Python 3 print , :

print(%3d %0.2f % (year,principal),file=f)

30 1.

, write(), - . , - print - :

f.write(%3d %0.2f\n % (year,principal))

, -. , - , sys.stdin. , sys.stdout, print. :

import sys

sys.stdout.write( :)

name = sys.stdin.readline()

Python 2 , :

name = raw_input( :)

Python 3 raw_input() input(), .

, , , :

a = , !

b = Python

c =

, - . , , - . - , , :

print Content-type: text/html

Hello World

Click here.

, , . - , s[i], :

31

a = ,

b = a[4] # b =

, s[i:j]. s k i >> x = 3.4

>>> str(x)

3.4

>>> repr(x)

3.3999999999999999

>>>

3.4 - Python. , - - .

32 1.

format(). :

>>> format(x,0.5f)

3.40000

>>>

. - , :

names = [ Dave, Mark, Ann, Phil ]

, , . :

a = names[2] # , Ann

names[0] = Jeff # Jeff

ap-pend():

names.append(Paula)

insert():

names.insert(2, Thomas)

:

b = names[0:2] # [Jeff, Mark]

c = names[2:] # [Thomas, Ann, Phil, Paula]

names[1] = Jeff # Jeff

names[0:2] = [Dave,Mark,Jeff] #

# .

(+) :

a = [1,2,3] + [4,5] # [1,2,3,4,5]

:

names = [] #

names = list() #

, , :

a = [1,Dave,3.14, [Mark, 7, 9, [100,101]], 10]

- , :

33

a[1] # Dave

a[3][2] # 9

a[3][3][1] # 101

1.2 . , , - .

1.2.

import sys # sys

if len(sys.argv) != 2 : # :

print ,

raise SystemExit(1)

f = open(sys.argv[1]) # ,

lines = f.readlines() #

f.close()

#

fvalues = [float(line) for line in lines]

#

print : , min(fvalues)

print : , max(fvalues)

import - sys Python. -Python. -. - .

open() , - sys.argv. readlines() - .

[float(line) for line in lines] , - float() . , , - . - for, , , :

fvalues = [float(line) for line in open(sys.argv[1])]

, - , min() max() .

-, -. , :

stock = (GOOG, 100, 490.10)

34 1.

address = (www.python.org, 80)

person = (first_name, last_name, phone)

Python , -Python , - , - :

stock = GOOG, 100, 490.10

address = www.python.org,80

person = first_name, last_name, phone

, -, 0 1 , :

a = () # ( )

b = (item,) # ( )

c = item, # ( )

-, . , :

name, shares, price = stock

host, port = address

first_name, last_name, phone = person

, ( , ), ( , - ). , , , .

- , - . , , ( ), - , . - , , , , . , , . . - .

. , , - , :

# name,shares,price

filename = portfolio.csv

portfolio = []

35

for line in open(filename):

fields = line.split(,) #

name = fields[0] #

shares = int(fields[1])

price = float(fields[2])

stock = (name,shares,price) # (name, shares, price)

portfolio.append(stock) #

split() - . portfolio, -, . , :

>>> portfolio[0]

(GOOG, 100, 490.10)

>>> portfolio[1]

(MSFT, 50, 54.23)

>>>

:

>>> portfolio[1][1]

50

>>> portfolio[1][2]

54.23

>>>

:

total = 0.0

for name, shares, price in portfolio:

total += shares * price

. set(), - , :

s = set([3,5,9,10]) #

t = set(Hello) #

, - - . , . , , - , :

>>> t

set([H, e, l, o])

, l.

36 1.

, , , . :

a = t | s # t s

b = t & s # t s

c = t s # (, t, s)

d = t ^ s # (, t s,

# )

add() update() :

t.add(x) #

s.update([10,37,42]) # s

remove():

t.remove(H)

, , , . , - ({}), :

stock = {

name : GOOG,

shares : 100,

price : 490.10

}

- :

name = stock[name]

value = stock[shares] * stock[price]

:

stock[shares] = 75

stock[date] = June 7, 2007

, , Py-Py-thon, . , , , - .

, , . , , , . , :

37

prices = {

GOOG : 490.10,

AAPL : 123.50,

IBM : 91.50,

MSFT : 52.13

}

:

prices = {} #

prices = dict() #

- in, :

if SCOX in prices:

p = prices[SCOX]

else:

p = 0.0

:

p = prices.get(SCOX,0.0)

, :

syms = list(prices) # syms = [AAPL, MSFT, IBM, GOOG]

del:

del prices[MSFT]

, , Python. - , -, .

for, - . Python. -Python. -. - -, , . :

for n in [1,2,3,4,5,6,7,8,9]:

print 2 %d = %d % (n, 2**n)

n - [1,2,3,4,,9]. - , :

38 1.

for n in range(1,10):

print 2 %d = %d % (n, 2**n)

range(i,j [,stride]) , - i j-1. , . stride - . :

a = range(5) # a = 0,1,2,3,4

b = range(1,8) # b = 1,2,3,4,5,6,7

c = range(0,14,3) # c = 0,3,6,9,12

d = range(8,1,-1) # d = 8,7,6,5,4,3,2

range() Python 2, . -. Python -Python - - xrange(). :

for i in xrange(100000000): # i = 0,1,2,...,99999999

xrange() , . - . Python 3 xrange() range(), range() .

for , , , , . :

a = ,

# a

for c in a:

print c

b = [Dave,Mark,Ann,Phil]

#

for name in b:

print name

c = { GOOG : 490.10, IBM : 91.50, AAPL : 123.15 }

#

for key in c:

print key, c[key]

#

f = open(foo.txt)

for line in f:

print line,

for Python, - -, . -

39

, - 6 .

def, :

def remainder(a, b):

q = a // b # // .

r = a - q*b

return r

, , , : result = re- = re-re-mainder(37, 15). , , :

def divide(a, b):

q = a // b # a b , q

r = a - q*b

return (q,r)

, - , :

quotient, remainder = divide(1456, 33)

:

def connect(hostname, port, timeout=300):

#

- - , . - , . :

connect(www.python.org, 80)

-, . , - . :

connect(port=80, hostname=www.python.org)

, - . , , - . - , global:

40 1.

count = 0

...

def foo():

global count

count += 1 # count

, yield, . :

def countdown(n):

print !

while n > 0:

yield n # (n)

n -= 1

, yield, -. - , - next() ( __next__() Python 3). :

>>> c = countdown(5)

>>> c.next()

!

5

>>> c.next()

4

>>> c.next()

3

>>>

next() - , yield. next() - , yield, . next() - , , yield. , .

, next() , . - - for, :

>>> for i in countdown(5):

... print i,

!

5 4 3 2 1

>>>

- . , - - tail -f, -

41

UNIX :

# ( tail -f)

import time

def tail(f):

f.seek(0,2) #

while True:

line = f.readline() #

if not line: # ,

time.sleep(0.1) #

continue #

yield line

, :

def grep(lines, searchtext):

for line in lines:

if searchtext in line: yield line

, - :

# tail -f | grep python

# Python

wwwlog = tail(open(access-log))

pylines = grep(wwwlog,python)

for line in pylines:

print line,

, - , . , , for item in s, s , , - - , -. s .

-. , , , . , yield, (yield), - :

def print_matches(matchtext):

print , matchtext

while True:

line = (yield) #

42 1.

if matchtext in line:

print line

, - , - (yield), send(). :

>>> matcher = print_matches(python)

>>> matcher.next() # (yield)

python

>>> matcher.send(Hello World)

>>> matcher.send(python is cool)

python is cool

>>> matcher.send(yow!)

>>> matcher.close() # matcher

>>>

, send(). , (yield) . -, (yield) . -, , close(), .

-, --, , . - . , :

#

matchers = [

print_matches(python),

print_matches(guido),

print_matches(jython)

]

# next()

for m in matchers: m.next()

# .

# : ,

# - .

wwwlog = tail(open(access-log))

for line in wwwlog:

for m in matchers:

m.send(line) #

6.

43

, , . , - . - , , . :

items = [37, 42] #

items.append(73) # append()

dir() . :

>>> items = [37, 42]

>>> dir(items)

[__add__, __class__, __contains__, __delattr__, __delitem__,

...

append, count, extend, index, insert, pop,

remove, reverse, sort]

>>>

, append() insert(). , - , . . , __add__() +:

>>> items.__add__([73,101])

[37, 42, 73, 101]

>>>

- class. , - , push(), pop() length():

class Stack(object):

def __init__(self): #

self.stack = [ ]

def push(self,object):

self.stack.append(object)

def pop(self):

return self.stack.pop()

def length(self):

return len(self.stack)

class Stack(object) -, Stack . , ; Stack object, - Python. -Python. -. - , def. -

44 1.

. self. , , self. , -, . , __init__() - .

:

s = Stack() #

s.push(Dave) #

s.push(42)

s.push([3,4,5])

x = s.pop() # x [3,4,5]

y = s.pop() # y 42

del s # s

, . . - list - :

class Stack(list):

# push()

# : pop().

def push(self,object):

self.append(object)

, , - ( -). , , C++ Java:

class EventHandler(object):

@staticmethod

def dispatcherThread():

while (1):

#

...

EventHandler.dispatcherThread() #

@staticmethod -. @staticmethod , 6.

- , , :

Traceback (most recent call last):

File foo.py, line 12, in

IOError: [Errno 2] No such file or directory: file.txt

45

(:

( ):

foo.py, 12,

IOError: [Errno 2] : file.txt

)

, . . - try except, :

try:

f = open(file.txt,r)

except IOError as e:

print e

IOError, - e - except. - , ( ). , except . , except. , - .

raise. raise -, :

raise RuntimeError( )

, 5 - .

, , - , , . - - with, . , -:

import threading

message_lock = threading.Lock()

...

with message_lock:

messages.add(newmessage)

with - message_lock. with, . , , with. , -

46 1.

, .

with , - , , . - . - 3 .

- , . Python , -. , , - . ( , .py.) :

# : div.py

def divide(a, b):

q = a/b # a b , q

r = a - q*b

return (q, r)

import:

import div

a, b = div.divide(2305, 29)

import - , - .py. , - , div.divide() .

, import as, - :

import div as foo

a,b = foo.divide(2305,29)

, from:

from div import divide

a,b = divide(2305,29) # div

, :

47

from div import *

dir() - , - :

>>> import string

>>> dir(string)

[__builtins__, __doc__, __file__, __name__, _idmap,

_idmapL, _lower, _swapcase, _upper, atof, atof_error,

atoi, atoi_error, atol, atol_error, capitalize,

capwords, center, count, digits, expandtabs, find,

...

>>>

Python -Python - - . -, - help() Python. -Python. -. - help() help(_), -. help() , .

Python -Python - -, . - , __doc__. :

>>> print issubclass.__doc__

issubclass(C, B) -> bool

Return whether class C is a subclass (i.e., a derived class) of class B.

When using a tuple as the second argument issubclass(X, (A, B, ...)),

is a shortcut for issubclass(X, A) or issubclass(X, B) or ... (etc.).

(

, C ( ) B.

issubclass(X, (A, B, ...)),

issubclass(X, A) or issubclass(X, B)

or ... ( . .).

)

>>>

, Py-Py-thon pydoc, Python. pydoc topic .

2.

, Python. , , - , , , - .

. , - (\), :

a = math.cos(3 * (x - n)) + \

math.sin(3 * (y - n))

-, , . , (...), [...], {...} , , .

, , , - . , . :

if a:

1 #

2

49

else:

3

4 # ()

, , , - , :

if a: 1

else: 2

pass. :

if a:

pass

else:

, . Py-Py-thon ( ) . Python , -Python , - , - , , 8 (, 11, 16). Python -t, , -, - . -tt, TabError.

-, (;). , , , .

# , -. , # , .

, , . .

, -, , , . - (_), .

50 2.

- AZ az ISO-Latin. -AZ az ISO-Latin. -Z az ISO-Latin. -Z az ISO-Latin. - az ISO-Latin. -az ISO-Latin. -z ISO-Latin. -z ISO-Latin. - ISO-Latin. -ISO-Latin. --Latin. -Latin. -. - , FOO foo . , $, % @. , , if, else for - . :

and del from nonlocal try

as elif global not while

assert else if or with

break except import pass yield

class exec in print

continue finally is raise

def for lambda return

, -, . , , - , _foo, - from module import *. , , __init__, . , - , __bar, - , 7 - -. .

Python :

True False , 1 0 . , 1234, . - , , 0, 0x 0b (, 0644, 0x100fea8 0b11101010).

Python , , , , , : 12345678901234567890.

51

1 , l ( L ) L, : 12345678901234567890L. - L , Python , - , , . Python, , L. -. , , ( L).

, 123.34 1.2334e+02, - . , j J, 12.34J, . , , : 1.2 + 12.34J.

, (), - () ( ). , - , , . - , - - ( , , ). ( , - ), hello world, - , : helloworld.

(\) , , , . - . 2.1. .

2.1.

\

\\

\

1 , repr(). . .

52 2.

\

\a

\b

\e

\0

\n

\v

\t

\r

\f

\OOO ( \000 \377)

\uxxxx ( \u0000 \uffff)

\Uxxxxxxxx ( \U00000000 \Uffffffff)

\N{ }

\xhh ( \x00 \xff)

\OOO \x , ( , , , ). - , . , Jalapeo, , Jalape\xf1o, \xf1 . Python 2 8- . . Python 2 . , , u . :

s = uJalape\u00f1o

Python 3 ( -Python 3 ( - 3 ( - ), - . Python 2 , -U ( - -, u ).

2.1 ()

53

Python -Python - - \u, \U \N . 2.1 - . , - U+XXXX, XXXX - . ( : Python, -Python, -, - .) , U+00F1. \u - U+0000 U+FFFF (-, \u00f1). \U U+10000 (-, \U00012345). \U , U+10000 , - . 3 .

, . - , \N{ }. :

s = uJalape\N{LATIN SMALL LETTER N WITH TILDE}o

http://www.unicode.org/charts.

r R, : r\d. , - , , . , , - . - , - re, Windows (, rc:\newdata\tests).

, r\. \uXXXX - , , \, - . , ur\u1234 - U+1234, ur\\u1234 , , u1234. , Py-Py-thon 2.2 r u, -. Python 3.0 u .

,

54 2.

, UTF-8 UTF-16. , UTF-8, Jalape\xc3\xb1o, - U+004A, U+0061, U+006C, U+0061, U+0070, U+0065, U+00C3, U+00B1, U+006F, , , . , UTF-8 \xc3\xb1 U+00F1, U+00C3 U+00B1. -, b, : bJalape\xc3\xb1o. , - . , decode(). 3 4 .

, - Python 2.6, . Python 3 bytes, (. - A, Python 3).

, [...], (...) {...} , , , , :

a = [ 1, 3.4, hello ] #

b = ( 10, 20, 30 ) #

c = { a: 3, b: 42 } #

, - , (\). , - . :

a = [ 1,

3.4,

hello,

]

,

Python :

+ - * ** / // % > & |

^ ~ < > = == != +=

-= *= /= //= %= **= &= |= ^= >>=

55

, , :

( ) [ ] { } , : . ` = ;

, (=) -, (,) , . (.) - , (...) - .

, :

# \ @

$ ? - , .

, - , , , :

def fact(n):

if (n >> print fact._ _doc__

>>>

- , . , . - .

, - , , , , . @ , - , . :

56 2.

class Foo(object):

@staticmethod

def bar():

pass

, . :

@foo

@bar

def spam():

pass

6 7 - .

Python -Python - - 7- ASCII. , , -, - .

Python , , :

#!/usr/bin/env python

# -*- coding: UTF-8 -*-

s = Jalapeo # UTF-8. coding: - , -, . Python, -Python, -, - , ASCII.

3.

, Python, . , , , . - . , . Python . - 4 . - 7 - .

, Python, - . , ( ) . , a = 42, 42. , , a , .

, , , . . . , . , . , - , , -.

. , .

58 3.

, , -, . - (.), :

a = 3 + 4j #

r = a.real # ()

b = [1, 2, 3] #

b.append(7) # append

#

, , id(). , , - Python, -Python, -, - . is . type() . :

#

def compare(a,b):

if a is b:

# a b

if a == b:

# a b

if type(a) is type(b):

# a b

, . - . - is. , . , list, dict file, - . :

if type(s) is list:

s.append(item)

if type(d) is dict:

d.update(t)

, - isinstance(object, type). :

if isinstance(s,list):

s.append(item)

59

if isinstance(d,dict):

d.update(t)

isinstance() , Python.

, , . -, . -, , - . , isinstance(s,list) , , , , , -, list. , , . - - - - - -- 7.

. , , , , :

a = 37 # 37

b = a # 37

c = []

c.append(b) # 37

, 37. a, , . - a b, b , 1. , b , - . , 37. - .

, del ( - ). :

del a # 37

b = 42 # 37

c[0] = 2.0 # 37

- sys.getrefcount(). :

>>> a = 37

>>> import sys

60 3.

>>> sys.getrefcount(a)

7

>>>

, . , , - , .

, - . , -. :

a = { }

b = { }

a[b] = b # a b

b[a] = a # b a

del a

del b

del a b , . - , - ( - ). , , . , -, - . gc (. 13, Python ).

, a = b, - b. , , b. , , . :

>>> a = [1,2,3,4]

>>> b = a # b a

>>> b is a

True

>>> b[2] = -100 # b

>>> a # , a

[1, 2, -100, 4]

>>>

61

a b , - , , . , .

, , - : -. , , . :

>>> a = [ 1, 2, [3,4] ]

>>> b = list(a) # a.

>>> b is a

False

>>> b.append(100) # b.

>>> b

[1, 2, [3, 4], 100]

>>> a # , a

[1, 2, [3, 4]]

>>> b[2] [0] = -100 # b

>>> b

[1, 2, [-100, 4], 100]

>>> a # , a

[1, 2, [-100, 4]]

>>>

a b , , , . - a b.

- , . Python , . - copy.deepcopy(), - :

>>> import copy

>>> a = [1, 2, [3, 4]]

>>> b = copy.deepcopy(a)

>>> b[2] [0] = -100

>>> b

[1, 2, [-100, 4]]

>>> a # , a

[1, 2, [3, 4]]

>>>

Python -Python - -. , , , - . , , -

62 3.

, , . , , :

items = {

number : 42

text : Hello World

}

, . :

items[func] = abs # abs()

import math

items[mod] = math #

items[error] = ValueError #

nums = [1,2,3,4]

items[append] = nums.append #

, , . - , . -:

>>> items[func](-45) # abs(-45)

45

>>> items[mod].sqrt(4) # math.sqrt(4)

2.0

>>> try:

... x = int(a lot)

... except items[error] as e: # except ValueError as e

... print(Couldnt convert)

...

Couldnt convert

>>> items[append](100) # nums.append(100)

>>> nums

[1, 2, 3, 4, 100]

>>>

, Python -Python - - , , -. , , , GOOG,100,490.10, , . - : ( ) - :

>>> line = GOOG,100,490.10

>>> field_types = [str, int, float]

>>> raw_fields = line.split(,)

>>> fields = [ty(val) for ty,val in zip(field_types,raw_fields)]

>>> fields

[GOOG, 100, 490.10000000000002]

>>>

63

Python , -Python , - , - . , . 3.1. , - , isinstance(). Python 2, ( Py-Python 2, ( Py- 2, ( Py-Py-thon 3 ).

3.1.

None type(None) None.

int

long

float

complex

bool

( Python 2)

(True False)

str

unicode

list

tuple

xrange

( Python 2)

, xrange() ( Python 3 range)

dict

set

frozenset

None None (, ). Python -Python - -, None. - , . None , , - . None - False.

64 3.

Python : , , , . , - . - .

: True False. True False 1 0 . - 2147483648 2147483647 ( ). ( -). , , Python (-Python (- (-, Python 3 ). , , , , - . - - . Python 2 isinstance(x, int) False, x .

Python - (64 ). , IEEE 754, -IEEE 754, - 754, - 17 , 308 308. double - C. Python 32- . - , numpy ( : http://numpy.sourceforge.net).

. - z z.real z.imag. z.conjugate() - z ( a+bj a-bj).

, . ( - fractions) numerator denominator. - real imag, conjugate(). , - , as_integer_ratio(). is_integer() ,

65

. hex() fromhex() - .

- . decimal - . fractions . 14 .

, - . , -. , . ; -, . .

,

. 3.2 , - . i- s s[i]. s[i:j] s[i:j:stride] ( 4). len(s). - min(s) max(s). -, , ( ). sum(s) , .

. 3.3 , - . 3.3 , -. 3.3 , -. 3.3 , -3.3 , - , .

3.2. ,

s[i] i- s

s[i:j]

s[i:j:stride]

len(s) s

min(s) - s

max(s) - s

66 3.

sum(s [,initial]) s

all(s) , - s, True

any(s) , - s, True

3.3. ,

s[i] = v

s[i:j] = t

s[i:j:stride] = t

del s[i]

del s[i:j]

del s[i:j:stride]

, , . 3.4. list(s) . s , , - . s.append(x) - x. s.index(x) x. - ValueError. s.remove(x) x Val-ueError, . s.extend(t) - s, t.

s.sort() . - . , . -, , . s.reverse() . , sort() reverse(), None.

3.2 ()

67

3.4.

list(s) s .

s.append(x) x s.

s.extend(t) t s.

s.count(x) x s.

s.index(x [,start [,stop]]) i, s[i] == x. start stop - , .

s.insert(i,x) x i.

s.pop([i]) i- . i , .

s.remove(x) s x - .

s.reverse() s .

s.sort([key [, reverse]]) s. key , . reverse - . key reverse - .

Python 2 . -Python 2 . - 2 . - , 8- . NULL. -, 16- . - -- 65 536 . 1 , Python . , (4--) , ; . - Python 32- . , Python U+000000 U+110000. , , - .

, . 3.5. , -

68 3.

, . -, s.capitalize(), s.center() s.expandtabs(), s . , s.isalnum() s.isupper(), True False, - . , - False .

s.find(), s.index(), s.rfind() s.rindex() . - s. , , find() -1, index() ValueError. s.replace() . , -. - re.

s.split() s.rsplit() -, . s.partition() s.rpartition() - - s : , - .

start end, , - s. , - .

s.translate() , , . , - -- - . 8- 256- . s, s[n] , - n.

s.encode() s.decode() , : ascii, utf-8 utf-16. - , - - 9 . , Python 3 encode() , decode() bytes.

s.format() . . - s {item} . {0}, {1} . . {name}, name . :

69

>>> a = {0} {age}

>>> a.format(, age=40)

40

>>>

{item} - . {item[n]}, n , n- item. - {item[key]}, key , item[key]. {item.attr} - attr item. format() - 4.

3.5.

s.capitalize() -.

s.center(width [, pad]) width. pad , .

s.count(sub [,start [,end]]) sub.

s.decode([encoding [,errors]]) ( ).

s.encode([encoding [,errors]]) ( ).

s.endswith(suffix [,start [,end]]) , - suffix.

s.expandtabs([tabsize]) .

s.find(sub [, start [,end]]) sub -1.

s.format(*args, **kwargs) s.

s.index(sub [, start [,end]]) sub .

s.isalnum() , - - .

s.isalpha() , - .

s.isdigit() , - .

s.islower() , - .

s.isspace() , - .

70 3.

s.istitle() , .

s.isupper() , - .

s.join(t) , - t, s -.

s.ljust(width [, fill]) s width.

s.lower() .

s.lstrip([chrs]) , chrs.

s.partition(sep) - sep. (head,sep,tail) (s, ,), sep s.

s.replace(old, new [,maxreplace]) old new.

s.rfind(sub [,start [,end]]) .

s.rindex(sub [,start [,end]]) .

s.rjust(width [, fill]) s width.

s.rpartition(sep) - sep, .

s.rsplit([sep [,maxsplit]]) , , - sep. maxsplit . maxsplit -, split().

s.rstrip([chrs]) , chrs.

s.split([sep [,maxsplit]]) - sep. maxsplit - .

s.splitlines([keepends]) . keepnds 1, - .

3.5 ()

71

s.startswith(prefix [,start [,end]]) , - prefix.

s.strip([chrs]) , chrs.

s.swapcase() , .

s.title() , - - .

s.translate(table [,deletechars]) - table, - ,

deletechars.

s.upper() .

s.zfill(width) - width.

xrange()

xrange([i,]j [,stride]) , - k, i

72 3.

, , ( , ).

m[k], k . , KeyError. len(m) , . - , , . 3.6.

3.6. ,

len(m) m.

m[k] m k.

m[k]=x m[k] x.

del m[k] m[k].

k in m True, k m.

m.clear() m.

m.copy() m.

m.fromkeys(s [,value]) , - s, - value.

m.get(k [,v]) m[k], , - v.

m.has_key(k) True, m k, - False. ( - in. Python 2.)

m.items() (key, value).

m.keys() .

m.pop(k [,default]) m[k], , ; default, , KeyError.

m.popitem() (key, value) - .

m.setdefault(k [, v]) m[k], , - v m[k] = v.

m.update(b) b m.

m.values() m.

73

, . 3.6, - . m.clear() . m.update(b) (key,value), b. m.get(k [,v]) - v, . m.setdefault(k [,v]) m.get(), , v - , m[k] = v. v , None. m.pop() . m.popitem() - .

m.copy() - . m.fromkeys(s [,value]) - , s. , m. - None, value . - fromkeys() , , , : dict.fromkeys().

m.items() , (key, value). m.keys() , m.values() . . Python 2 , Python 3 - , . - , Python. , . , items = list(m.items()). , keys = list(m).

. , . , . , , . : set - , frozenset . - :

s = set([1,5,10,15])

f = frozenset([a,37,hello])

, set() frozenset(), , - , . - , . 3.7.

74 3.

3.7. ,

len(s) s.

s.copy() s.

s.difference(t) . s, t.

s.intersection(t) . , s t.

s.isdisjoint(t) True, s t - .

s.issubset(t) True, s - t.

s.issuperset(t) True, s - t.

s.symmetric_difference(t) . , s t, .

s.union(t) . , s t.

s.difference(t), s.intersection(t), s.symmetric_difference(t) s.union(t) . - , s (set frozenset). t Python, . , , . - , 4.

( set) , . 3.8.

3.8. ,

s.add(item) item s. , .

s.clear() s.

s.difference_update(t) s, - t.

s.discard(item) item s. -, .

s.intersection_update(t) s t s.

s.pop() s.

75

s.remove(item) item s. item - , KeyError.

s.symmetric_difference_

update(t)

s t s.

s.update(t) t s. t , , .

s. t - , .

, Python , -Python , - , - , . . 3.9 - , - .

3.9. Python

types.BuiltinFunctionType

type

object

types.FunctionType

types.MethodType

types.ModuleType

object

type

, . 3.9 object type , - , , .

, , . , , , - , .

76 3.

, def lambda. :

def foo(x,y):

return x + y

bar = lambda x,y: x + y

f :

f.__doc__

f.__name__

f.__dict__ ,

f.__code__ -

f.__defaults__

f.__globals__ ,

f.__closure__ , ,

Python 2 , func_code, func_defaults . - Python 2.6 Python 3.

, . : , - :

class Foo(object):

def instance_method(self,arg):

@classmethod

def class_method(cls,arg):

@staticmethod

def static_method(arg):

, . , - self. - , . - cls. ,

77

. - , .

types.MethodType. , , , , - (.). (.) , . , - . f.instance_method(arg) Foo :

f = Foo() #

meth = f.instance_method # ()

meth(37) #

meth . - , () . - (self). meth -, , , - () .

- . :

umeth = Foo.instance_method # instance_method Foo

umeth(f,37) # self

umeth . , , , - . f Foo. , TypeError. :

>>> umeth(hello,5)

Traceback (most recent call last):

File , line 1, in

TypeError: descriptor instance_method requires a Foo object but received a str

(:

( ):

, 1,

TypeError: instance_method Foo,

str

)

>>>

- types.MethodType, - . :

78 3.

m.__doc__

m.__name__

m.__class__ ,

m.__func__ ,

m.__self__ , (None )

Python 3 , -Python 3 , - 3 , - types.MethodType. - Foo.instance_method, , , , . , Python 3 self.

, C C++, types.BuiltinFunctionType. - :

b.__doc__

b.__name__ /

b.__self__ , ( )

, len(), __self__ - None, , - . , x.append, x , __self__ x.

, -. class . - __init__() - . , __call__(). x, x(args) x.__call__(args).

79

, , type. :

>>> class Foo(object):

... pass

...

>>> type(Foo)

t type, - :

t.__doc__

t.__name__

t.__bases__

t.__dict__ ,

t.__module__ ,

t.__abstractmethods__ ( , )

, , - . :

>>> f = Foo()

>>> type(f)

i:

i.__class__ ,

i.__dict__ ,

__dict__ , - , - , - , - , - , - , - , - , -, -, -- . , i.attr = value, value . , __slots__, - , __dict__. Python 7.

80 3.

, , - import. , import foo, foo . - , , __dict__. , - ( ), - . , m.x -- m.__dict__[x]. , : m.x = y, m.__dict__[x] = y. :

m.__dict__ ,

m.__doc__

m.__name__

m.__file__ ,

m.__path__ . , -

, , - . -, , , , Ellipsis. . 3.10. , .

3.10.

types.CodeType -

types.FrameType

types.GeneratorType

types.TracebackType

slice

Ellipsis

81

, - , -, compile(). , , , , , - . c - , :

c.co_name

c.co_argcount ( )

c.co_nlocals , -

c.co_varnames

c.co_cellvars , -

c.co_freevars . ,

c.co_code -

c.co_consts , -

c.co_names , -

c.co_filename ,

c.co_firstlineno

c.co_lnotab , -

c.co_stacksize ( )

c.co_flags , -. 2 (0x04) , - (*args). 3 (0x08) , (**kwds). -

- -

82 3.

( ). f , :

f.f_back ( )

f.f_code

f.f_locals ,

f.f_globals ,

f.f_builtins ,

f.f_lineno

f.f_lasti . - f_code

( - ):

f.f_trace , -

f.f_exc_type ( Python 2)

f.f_exc_value ( Python 2)

f.f_exc_traceback - ( Python 2)

- . sys.exc_info(). , :

t.tb_next , - ( , - )

t.tb_frame ,

t.tb_lineno ,

t.tb_lasti ( ), -

83

- (- 6 -). - , - yield. -. :

g.gi_code -

g.gi_frame -

g.gi_running , -

g.next() -, yield, ( Python 3 __next__())

g.send(value) value . yield -. - -, yield. send() - , - yield

g.close() , - GeneratorExit -. ,

g.throw(exc [,exc_value [,exc_tb ]]) - yield. exc , exc_value exc_tb - -. , , yield

, - , : a[i:j:stride], a[i:j, n:m]

84 3.

a[..., i:j]. slice([i,] j [,stride]). , :

s.start . None, .

s.stop . None, .

s.step . None, .

s.indices(length). (start,stop,stride) . :

s = slice(10,20) # [10:20]

s.indices(100) # (10,20,1) > [10:20]

s.indices(15) # (10,15,1) > [10:15]

Ellipsis Ellipsis (ellipsis) []. , El-lipsis. , True. Ellipsis Python, , -Python, , -, , - [] - . , Ellipsis :

class Example(object):

def __getitem__(self,index):

print(index)

e = Example()

e[3, ..., 4] # e.__getitem__((3, Ellipsis, 4))

Python , . , -, , , , -, s[n], len(s) . . - - (__). - . , x + y x.__add__(y), x[k] x.__getitem__(k).

85

, .

, - , , -. , - ( ) - , .

, .

, . 3.11, , -, . 3.11, , - . 3.11, , - . 3.11, , - . 3.11, , - . 3.11, , -. 3.11, , -. 3.11, , -3.11, , - . __new__() , . __init__() - . __del__() . , . , del x - . 7.

3.11.

__new__(cls [,*args [,**kwargs]]) .

__init__(self [,*args [,**kwargs]])

__del__(self)

__new__() __init__() - . A(args), - :

x = A.__new__(A,args)

is isinstance(x,A): x.__init__(args)

__new__() __del__(). __new__() - , ( , , ). __del__() , - , - .

86 3.

. 3.12 , .

3.12.

__format__(self, format_spec) -

__repr__(self)

__str__(self)

__repr__() __str__() . __repr__() , - - eval(). , - . - repr(). repr() eval():

a = [2,3,4,5] #

s = repr(a) # s = [2, 3, 4, 5]

b = eval(s) #

- - , , __repr__() , :

f = open(foo)

a = repr(f) # a =

__str__() str(), -, . __repr__() , - . __repr__().

__format__() format() format(). format_spec , - . , format(), , format_spec format(). -:

format(x,spec) # x.__format__(spec)

x is {0:spec}.format(x) # x.__format__(spec)

87

- . -, 4.

. 3.13 , - . 3.13 , -. 3.13 , -. 3.13 , -3.13 , - . __bool__() True False. , - __len__(). __hash__() , . -, . , ; - , - .

3.13.

__bool__(self) False True

__hash__(self) -

- (, =, ==, !=). - , Boolean, Python. , , , - . , . , , . 3.14.

3.14. ,

__lt__(self,other) self < other

__le__(self,other) self other

__ge__(self,other) self >= other

__eq__(self,other) self == other

__ne__(self,other) self != other

88 3.

- , . 3.14. -3.14. - -, == - , __eq__(). , - , min() max(), -, , __lt__().

. 3.15 , - , - isinstance() b issubclass(). - , 7.

3.15.

__instancecheck__(cls,object) isinstance(object, cls)

__subclasscheck__(cls, sub) issubclass(sub, cls)

. 3.16 , /- . 3.16 , /-. 3.16 , /-. 3.16 , /-3.16 , /- (.) del .

3.16.

__getattribute__(self,name) self.name.

__getattr__(self, name) self.name, , AttributeError.

__setattr__(self, name, value) - self.name = value. - , - .

__delattr__(self, name) self.name.

__getattribute__() , - . , . __get-attr__(). __getattr__() Attrib-uteError. __setattr__(), __delattr__().

89

- , - , , . - , , - . 3.17. , .

3.17. -

__get__(self,instance,cls) - AttributeError

__set__(self,instance,value) value

__delete__(self,instance)

__get__(), __set__() __delete__() __getattribute__(), __setattr__() __delattr__() . - . - . - . - . - . - . -. -. - - , - . , , . - -, , -, . 7.

. 3.18 , , - .

3.18.

__len__(self) self

__getitem__(self, key) self[key]

__setitem__(self, key, value) self[key] = value

__delitem__(self, key) self[key]

__contains__(self, obj) True, obj self; False

90 3.

:

a = [1,2,3,4,5,6]

len(a) # a.__len__()

x = a[2] # x = a.__getitem__(2)

a[1] = 7 # a.__setitem__(1,7)

del a[2] # a.__delitem__(2)

5 in a # a.__contains__(5)

__len__() len() - . , __bool__() - .

- __getitem__(), , key. Python, . __setitem__() - - - - - - -- value . __delitem__() , del . __contains__() in.

, __getitem__(), __setitem__() __deli-deli-tem__() , x = s[i:j]. - - slice. , - . :

a = [1,2,3,4,5,6]

x = a[1:5] # x = a.__getitem__(slice(1,5,None))

a[1:3] = [10,11,12] # a.__setitem__(slice(1,3,None), [10,11,12])

del a[1:4] # a.__delitem__(slice(1,4,None))

, Python, -Python, -, - , . , - , , :

a = m[0:100:10] # (=10)

b = m[1:10, 3:20] #

c = m[0:100:10, 50:75:5] #

m[0:5, 5:10] = n #

del m[:10, 15:] #

i:j[:stride], stride () . , - . , - (- ...) :

91

a = m[..., 10:20] #

m[10:20, ...] = n

, __get-get-item__(), __setitem__() __delitem__() . - , - Ellipsis. ,

a = m[0:10, 0:100:5, ...]

__getitem__():

a = m.__getitem__((slice(0,10,None), slice(0,100,5), Ellipsis))

, Python -Python - - , - 4. Python, , - .

obj , obj.__iter__(), . iter, , iter.next() ( iter.__next__() Python 3), -Python 3), - 3), - StopIteration . - for , - . , for x in s :

_iter = s.__iter__()

while 1:

try:

x = _iter.next() # _iter.__next__() Python 3

except StopIteration:

break

# , for

...

. 3.19 , - . 3.19 , -. 3.19 , -. 3.19 , -3.19 , - . , , 4; , x + y, - x.__add__(y). , - r, , - . , . , x, x + y, __add__(), y.__radd__(x).

92 3.

3.19.

__add__(self,other) self + other

__sub__(self,other) self - other

__mul__(self,other) self * other

__div__(self,other) self / other ( Python 2)

__truediv__(self,other) self / other (Python 3)

__floordiv__(self,other) self // other

__mod__(self,other) self % other

__divmod__(self,other) divmod(self,other)

__pow__(self,other [,modulo]) self ** other, pow(self, other, modulo)

__lshift__(self,other) self > other

__and__(self,other) self & other

__or__(self,other) self | other

__xor__(self,other) self ^ other

__radd__(self,other) other + self

__rsub__(self,other) other - self

__rmul__(self,other) other * self

__rdiv__(self,other) other / self ( Python 2)

__rtruediv__(self,other) other / self (Python 3)

__rfloordiv__(self,other) other // self

__rmod__(self,other) other % self

__rdivmod__(self,other) divmod(other,self)

__rpow__(self,other) other ** self

__rlshift__(self,other) other > self

__rand__(self,other) other & self

__ror__(self,other) other | self

__rxor__(self,other) other ^ self

__iadd__(self,other) self += other

__isub__(self,other) self -= other

__imul__(self,other) self *= other

__idiv__(self,other) self /= other ( Python 2)

__itruediv__(self,other) self /= other (Python 3)

93

__ifloordiv__(self,other) self //= other

__imod__(self,other) self %= other

__ipow__(self,other) self **= other

__iand__(self,other) self &= other

__ior__(self,other) self |= other

__ixor__(self,other) self ^= other

__ilshift__(self,other) self = other

__neg__(self) self

__pos__(self) +self

__abs__(self) abs(self)

__invert__(self) ~self

__int__(self) int(self)

__long__(self) long(self) ( Python 2)

__float__(self) float(self)

__complex__(self) complex(self)

__iadd__(), __isub__() . . - , , a+=b a-=b ( -). - - - . , self , , .

, __div__(), __truediv__() __floordiv__(), (/) - (//). , Python 2.2, Python 3 /, . Python 2 / - __div__(). . Python 3 / __truediv__() - . Python 2 , -Python 2 , - 2 , - from __future__ import division.

__int__(), __long__(), __float__() __complex__() -, -

94 3.

. , int() float(). - . , - 3 + x TypeError, x __int__() .

, __call__(self [,*args [, **kwargs]]). x , , . x(arg1, arg2, ...) x.__call__(self, arg1, arg2, ...). , , -. :

class DistanceFrom(object):

def __init__(self,origin):

self.origin = origin

def __call__(self, x):

return abs(x - self.origin)

nums = [1, 37, 42, 101, 13, 9, -20]

nums.sort(key=DistanceFrom(10)) # 10

DistanceFrom, - . , sort(), - .

with , . :

with context [ as var]:

, context , . 3.20. __enter__() with. , , , as var. __exit__() -, , - with. __exit__() , -, - . None.

95

3.20.

__enter__(self) . , as with.

__exit__(self, type, value, tb) , - . - , type, value tb - , - . with -, , . - , . 5 -.

dir() dir() . , dir(), __dir__(self). - , . , , __dict__ .

4.

, Python. -Python. -. - , - - .

, - :

x + y

x y

x * y

x / y

x // y

x ** y (xy)

x % y (x mod y)

-x

+x

(//, , ) -, . Python 2 (/) , . 7/4 1, 1.75. - Python 3 ,

97

. x // y. , 7 % 4 3. x // y, - x (x // y) * y. (%) (//) .

, :

x > y

x & y

x | y

x ^ y

~x

, , -. , , . , Python , - .

, :

abs(x)

divmod(x,y) (x // y, x % y)

pow(x,y [,modulo]) (x ** y) % modulo

round(x,[n]) 10-n ( )

abs() . divmod() , . pow() **, ( -( - - -- ). round() x , 10 n. n , 0. x , Python 2

98 4.

, (, 0.5 1.0, -0.5 -1.0). Python 3, , - (, 0.5 0.0, 1.5 2.0). Python 3.

- True, -, False, :

x < y

x > y

x == y

x != y

x >= y

x z, - , , ( , x z ). - , , TypeError.

, - . - :

1. , .

2. , .

3. - .

, - , . -, , - .

99

, - , , :

s + r

s * n, n * s n s, n

v1,v2, vn = s

s[i]

s[i:j]

s[i:j:stride]

x in s, x not in s

for x in s:

all(s) True, s ,

any(s) True, - s ,

len(s)

min(s) s

max(s) s

sum(s [, initial])

+ . - s * n n . - - , . :

>>> a = [3,4,5]

>>> b = [a]

>>> c = 4*b

>>> c[[3, 4, 5], [3, 4, 5], [3, 4, 5], [3, 4, 5]]

>>> a[0] = -7

>>> c[[-7, 4, 5], [-7, 4, 5], [-7, 4, 5], [-7, 4, 5]]

>>>

, c. a - b. b - . , -

100 4.

a . - -. , , a. :

a = [ 3, 4, 5 ]

c = [list(a) for j in range(4)] # list()

, copy .

-. :

items = [ 3, 4, 5 ]

x,y,z = items # x = 3, y = 4, z = 5

letters = abc

x,y,z = letters # x = a, y = b, z = c

datetime = ((5, 19, 2008), (10, 30, am))

(month,day,year),(hour,minute,am_pm) = datetime

- -. , - . , -, 3 , . - -, , -.

s[n] n- -, s[0] . , - , - . , s[-1] . , -, IndexError.

s[i:j] , , k i

101

, s[i:j:stride], . - - - - - - - - - -- . stride, i j, - s[i], s[i+stride], s[i+2*stride] , j ( ). stride - - - - - - - - --. i, - , , . j, - , stride , stride . :

a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

b = a[::2] # b = [0, 2, 4, 6, 8 ]

c = a[::-2] # c = [9, 7, 5, 3, 1 ]

d = a[0:5:2] # d = [0,2]

e = a[5:0:-2] # e = [5,3,1]

f = a[:5:1] # f = [0,1,2,3,4]

g = a[:5:-1] # g = [9,8,7,6]

h = a[5::1] # h = [5,6,7,8,9]

i = a[5::-1] # i = [5,4,3,2,1,0]

j = a[5:0:-1] # j = [5,4,3,2,1]

x in s x s True False. x not in s - x s. in not in . , hello in hello world True. , in - . , - , re.

for x in s - 5 - . len(s) - . min(s) max(s) - ; , < (, ). sum(s) - s, . - . . , sum(items, decimal.Decimal(0)) - Decimal ( decimal - 14 ).

102 4.

- . - :

s[i] = x

s[i:j] = r

s[i:j:stride] = r

del s[i]

del s[i:j]

del s[i:j:stride]

s[i] = x i, - x x. - , , -, IndexError. - s[i:j] = r k, i

103

. , . , . a b, - , a < b.

. - , - ( ASCII ). , . , , . , - ( - unicodedata locale).

, . Python : . , , , . - (, + == ). - Python 3 TypeError, Python 2 . Py-Py-thon 2 - 2 - . , , - .

(s % d) , s , d (). sprintf() C. : ( ) , . d , - d. d , - ( - , ).

104 4.

% -, . 4.1.

4.1.

d, i .

u .

o .

x .

X ( - ).

f [-]m.dddddd.

e [-]m.ddddddexx.

E [-]m.ddddddExx.

g, G %e %E, -4 ; -

%f.

s . - str().

r , repr().

c .

% %.

% - :

1. , - . , - KeyError.

2. :

-, . .

+, ( ).

0, .

3. , . , , ( , ) .

4. , .

5. , - ; ,

105

, , .

, (*). , - .

:

a = 42

b = 13.142783

c = hello

d = {x:13, y:1.54321, z:world}

e = 5628398123741234

r = a is %d % a # r = a is 42

r = %10d %f % (a,b) # r = 42 13.142783

r = %+010d %E % (a,b) # r = +000000042 1.314278E+01

r = %(x)-10d %(y)0.3g % d # r = 13 1.54

r = %0.4s %s % (c, d[z]) # r = hell world

r = %*.*f % (5,3,b) # r = 13.143

r = e = %d % e # r = e = 5628398123741234

% , , - ( $var ). -, , - , :

stock = {

name : GOOG,

shares : 100,

price : 490.10 }

r = %(shares)d %(name)s %(price)0.2f % stock

# r = 100 GOOG 490.10

, - . vars() , - , .

name =

age = 41

r = %(name)s, %(age)s % vars()

s.format(*args, **kwargs) . - - s. {n}, n , - format(). {name}

106 4.

. - {, {{, }} }. :

r = {0} {1} {2}.format(GOOG,100,490.10)

r = {name} {shares} {price}.format(name=GOOG,shares=100,price=490.10)

r = , {0}, {age} .format(,age=47)

r = {{ }} .format()

- . , {name[n]}, n , n- - name, {name[key]}, key , name[key]. {name.attr} - name.attr. :

stock = { name : GOOG,

shares : 100,

price : 490.10 }

r = {0[name]} {0[shares]} {0[price]}.format(stock)

x = 3 + 4j

r = {0.real} {0.imag}.format(x)

- . , - .

- . -, (:), : {place:format_spec}. - , -. :

r = {name:8} {shares:8d} {price:8.2f}.format

(name=GOOG,shares=100,price=490.10)

[[fill[align]][sign][0][width][.precision][type], , [], -. width , - align , , . - fill , . :

name = Elwood

r = {0:10}.format(name) # r = Elwood

r = {0:^10}.format(name) # r = Elwood

r = {0:=^10}.format(name) # r = ==Elwood==

type . . 4.2 - . type ,

107

s, d f.

4.2.

d, i .

b .

o .

x .

X ( - ).

f, F [-]m.dddddd.

e [-]m.ddddddexx.

E [-]m.ddddddExx.

g, G e E, -4 ; - f.

n , g, - .

% 100 f, %.

s . str().

c .

sign - +, - . + , - . - , . , . precision -. width 0, - . :

x = 42

r = {0:10d}.format(x) # r = 42

r = {0:10x}.format(x) # r = 2a

r = {0:10b}.format(x) # r = 101010

r = {0:010b}.format(x) # r = 0000101010

y = 3.1415926

r = {0:10.2f}.format(y) # r = 3.14

r = {0:10.2e}.format(y) # r = 3.14e+00

108 4.

r = {0:+10.2f}.format(y) # r = +3.14

r = {0:+010.2f}.format(y) # r = +000003.14

r = {0:+10.2%}.format(y) # r = +314.16%

- , format(). . :

y = 3.1415926

r = {0:{width}.{precision}f}.format(y,width=10,precision=3)

r = {0:{1}.{2}f}.format(y,10,3)

- . , .

, - . format() __format__(self, format_spec) . format() . , , - -.

- , str() repr(), , __format__(). !s !r. :

name =

r = {0