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5/21/2018 Mainframe Sas Online Training 01 (1)
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Introduction to SAS and Basic Concepts
Statistical Analysis System
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Turning Data into Information
The process of delivering meaningfl information is typicallydistri!ted as
follo"s#
80% data-related
$ access
$ scr!
$ transform
$ manage
$ store and retrieve
20% analysis
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Basic concepts of SAS
'vervie"
SAS Programs
SAS (i!raries)eferencing SAS files
SAS data Sets
*aria!le Attri!tes
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Oerie!
To program effectively sing SAS, yo need to nderstand !asicconcepts a!ot SAS programsand the SAS files that they process- .n
particlar, yo need to !e familiar "ith SAS data sets-
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SAS "rogram
0o can se SAS programs to access, manage, analye, or present yordata-
(ets !egin !y looing at a simple SAS program-
DATA SAMPLE;INPUT NAME $10.;
DATALINES;
ANIL
ARUN;
RUN;
PROC PRINT DATA=SAMPLE;
RUN;
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Components of SAS "rograms # Sample code
'r sample SAS program contains t"o steps# a ATA stepand a P)' step-
DATA SAMPLE;
INPUT NAME $10.;DATALINES;
ANIL
ARUN;
RUN;PROC PRINT DATA=SAMPLE;
RUN;
Continued$
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Components of SAS "rograms # DATA ST"& "'OC ST"
T(ese t!o types of steps& alone or com)ined& form most SAS programs*
Continued$
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DATA steps typically create or modify SAS data sets- They can also !e sed to prodcecstom designed reports- 6or eample, yo can se ATA steps to
pt yor data into a SAS data set
compte vales
chec for and correct errors in yor data
prodce ne" SAS data sets !y s!setting, merging, and pdating eisting data sets-
"'OC +procedure, steps are pre8"ritten rotines that ena!le yo to analye and
process the data in a SAS data set and to present the data in the form of a report- P)'
steps sometimes create ne" SAS data sets that contain the reslts of the procedre-
P)' steps can list, sort, and smmarie data- 6or eample, yo can se P)' steps
to
create a report that lists the data
prodce descriptive statistics
create a smmary report
prodce plots and charts-
Components of SAS "rograms
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C(aracteristics of SAS "rograms
9et let:s loo at the individal statements in or sample program- SAS programs consistof SAS statements- A SAS statement has t"o important characteristics#
.t sally !egins "ith a SAS ey!ord-
.t al"ays ends "ith a semicolon
DATA SAMPLE; ---- SAS Data Step creating DataetINPUT NAME $10.;
DATALINES;
ANIL
ARUN;
RUN;
PROC PRINT DATA=SAMPLE; -- SAS PROC tep ! Printing DATA
RUN;
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.ayout for SAS "rograms
SAS statements are in free format- This means that
they can !egin and end any"here on a line
one statement can contine over several lines
several statements can !e on a line-;lans or special characters separate
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"rocessing SAS "rograms
>hen yo s!mit a SAS program, SAS !egins reading the statements and checingthem for errors- ATA and P)' statements signal the !eginning of a ne" step- >hen
SAS enconters a s!se=ent ATA, P)', or )?9 statement @for ATA steps and
most procedres or a B?.T statement @for some procedres, SAS stops reading
statements and eectes the previos step in the program- .n or sample program, each
step ends "ith a )?9 statement-
DATA SAMPLE; ---- SAS Data Step creating Dataet
INPUT NAME $10.;
DATALINES;
ANIL
ARUN;
RUN;
PROC PRINT DATA=SAMPLE; -- SAS PROC tep ! Printing DATA
RUN;
/oteThe !eginning of a ne" step @ATA or P)' implies the end of the previos
step- Thogh the )?9 statement is not al"ays re=ired !et"een steps in a
SAS program, sing it can mae the SAS program easier to read and de!g,
and it maes the SAS log easier to read-
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.og 1essages
Cach time a step is eected, SAS generates a log of the processing activities and the reslts of the
processing- The SAS log collects messages a!ot the processing of SAS programs and a!ot any errors
that occr- >hen SAS processes or sample program, yo see the log messages sho"n !elo"- 9otice that
yo get separate sets of messages for each step in the program-
SAS .og
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SAS .og and SAS .i)raries
Cvery SAS file is stored in a SAS li)rary, "hich is a collection of SAS files- ASAS data li!rary is the highest level of organiation for information "ithin SAS-
6or eample, in the >indo"s and ?9.D environments, a li!rary is typically a
grop of SAS files in the same folder or directory-
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SAS .i)raries
The ta!le !elo" smmaries the implementation of SAS li!raries in variosoperating environments-
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'eferencing SAS iles
To reference a SAS file, yo se a t"o8level name,libref.filename- .n the t"o8level name, libref is the name forthe SAS li!rary that contains the file, and filename is the name of the
file itself- A period separates the li!ref and filename-
To reference temporary SAS files, yo specify the defalt li!ref 3or,
a period, and the filename- Alternatively, yo can simply se a one8
level name @the filename only to reference a file in a temporary SAS
li!rary- )eferencing a SAS file in any li!rary e4cept 3or indicates
that the SAS file is stored permanently-
SAS data set names can !e 1 to 32 characters long, mst !egin "itha letter @A-E, either ppercase or lo"ercase or an nderscore @F,
and can contine "ith any com!ination of nm!ers, letters, or
nderscores-
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SAS Data Sets
6or many of the data processing tass that yo perform "ithSAS, yo access data in the form of a SAS data set andse SAS programs to analye, manage, or present the data-onceptally, a SAS data set is a file that consists of t"o
parts# a descriptor portion and a data portion-
The descriptor portion of a SAS data set contains information a!ot the data set-
The data portion of a SAS data set is a collection of data vales that are arranged in arectanglar ta!le-
O)serations in the data set correspond to ro"s or data lines in a ra" data file
or in an eternal data!ase- An o!servation is the information a!ot each o!Gect in a SASdata set-
5aria)les in the data set correspond to colmns in a ra" data file or in an eternaldata!ase-
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5aria)le Attri)utes
.n addition to general information a!ot the data set, the descriptorportion contains information a!ot the attri!tes of each varia!le in
the data set- The attri!te information incldes the
varia!le:s name,
type,
length, format,
informat, and
la!el-
/ame
Cach varia!le has a name that conforms to SAS naming conventions- *aria!le namesfollo" eactly the same rles as SAS data set names- (ie data set names, varia!le
names
can !e 1 to 32 characters long
mst !egin "ith a letter @A-E, either ppercase or lo"ercase or an nderscore @F
can contine "ith any com!ination of nm!ers, letters, or nderscores- Continued$
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5aria)le Attri)utes
9ame continedH
Type
A varia!le:s type is either c(aracter or numeric- haracter varia!les, sch as 9ame @sho"n !elo", can contain any alues-
9meric varia!les, sch as Policy and Total @sho"n !elo", can contain only numeric alues @the digits throgh +, I, 8, -, and C for
scientific notation-
Continued$
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.engt(
A varia!le:s lengt( @the nm!er of !ytes
sed to store it is related to its type- haracter varia!les can !e p to 62&77 )ytes long- .n the eample !elo", 9ame
has a length of 2 characters and ses 2 !ytes of storage-
All nmeric varia!les have a defalt length of 8- 9meric vales @no matter ho"
many digits they contain are stored as floating8point nm!ers in & !ytes of storage,
nless yo specify a different length-
5aria)le Attri)utes
Continued$
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5aria)le Attri)utes
ormat 6ormats are varia!le attri!tes that affect the "ay data vales are "ritten- SAS
soft"are offers a variety of character, nmeric, and date and time formats- 0o
can also create and store yor o"n formats- To "rite vales ot sing a
particlar form, yo select the appropriate format-
Continued$
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5aria)le Attri)utes
Informat
ormats "rite vales out !y sing some particlar form "hereas informats read data vales in
certain forms into standard SAS vales- .nformats determine ho" data vales are read into a SAS
data set- 0o must se informats to read nmeric vales that contain letters or other special
characters-
Continued$
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5aria)le Attri)utes
.a)elA varia!le can have a la)el, "hich consists of descriptive
tet p to 25% characters long- ;y defalt, many reports
identify varia!les !y their names- 0o might "ant to display
more descriptive information a!ot the varia!le !yassigning a la!el to the varia!le-
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