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大綱
何謂陣列 關連式陣列 陣列排序 數值索引陣列 多維陣列
何謂陣列
連續資料的集合 透過索引或 key 存取
數值索引陣列 $products = array(“Tires”, “Oil”, “Spark Plugs”); array() 是一個程式結構，不是函式 $products[0] 即 “ Tires” $products[1] 即 “ Oil” $products[2] 即 “ Spark Plugs” for ($i = 0; $i < 3; $i++)
echo “$products[$i]”; 可以隨時增加元素
$products[3] = “Fuses”;
range
Create an array containing a range of elements
array range ( int low, int high [, int step])
<?php// array(0,1,2,3,4,5,6,7,8,9)foreach(range(0, 9) as $number) { echo $number;}// The step parameter was introduced in 5.0.0// array(0,10,20,30,40,50,60,70,80,90,100)foreach(range(0, 100, 10) as $number) { echo $number;}// Use of characters introduced in 4.1.0// array('a','b','c','d','e','f','g','h','i');foreach(range('a', 'i') as $letter) { echo $letter;}// array('c','b','a');foreach(range('c', 'a') as $letter) { echo $letter;}?>
<?php// array(0,1,2,3,4,5,6,7,8,9)foreach(range(0, 9) as $number) { echo $number;}// The step parameter was introduced in 5.0.0// array(0,10,20,30,40,50,60,70,80,90,100)foreach(range(0, 100, 10) as $number) { echo $number;}// Use of characters introduced in 4.1.0// array('a','b','c','d','e','f','g','h','i');foreach(range('a', 'i') as $letter) { echo $letter;}// array('c','b','a');foreach(range('c', 'a') as $letter) { echo $letter;}?>
關連式陣列
$prices = array(“Tires” => 100,“Oil” => 10, “Spark Plugs” => 4);
$prices[“Tires”] 即 100 在迴圈中使用 each() 和 list() 存取陣列元素
each : Return the current key and value pair from an array and advance the array cursor If the internal pointer for the array points past the end of the
array contents, each() returns FALSE. List : Assign variables as if they were an array
list() only works on numerical arrays and assumes the numerical indices start at 0.
while ($element = each($prices)) { echo $element["key"]; echo "-"; echo $element["value"]; echo "<br>";}
while ($element = each($prices)) { echo $element["key"]; echo "-"; echo $element["value"]; echo "<br>";}
reset($prices);while (list($product, $price) = each($prices)) { echo "$product - $price <br>";}
reset($prices);while (list($product, $price) = each($prices)) { echo "$product - $price <br>";}
$prices = array("Tires"=>100,"Oil"=>10,"Spark Plugs"=>4);
$prices = array("Tires"=>100);$prices["Oil"] = 10;$prices["Spark Plugs"] = 4;
$prices = array("Tires"=>100,"Oil"=>10,"Spark Plugs"=>4);
$prices = array("Tires"=>100);$prices["Oil"] = 10;$prices["Spark Plugs"] = 4;
多維陣列
$products = array(array(“TIR”, “Tires”, 100),array(“OIL”, “Oil”, 10),array(“SPK”, “Spark Plugs”, 4));
$product[0][0] 即 “ TIR”
陣列排序
數值索引陣列 sort() 升冪（從小到大）排序
關連式陣列 asort()
Sort an array and maintain index association ksort()
Sort an array by key
逆向排序（降冪，從大到小） rsort() 、 arsort() 、 krsort()
$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");asort ($fruits);reset ($fruits);while (list ($key, $val) = each ($fruits)) { echo "$key = $val\n";}
This example would display:
c = appleb = bananad = lemona = orange
$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");ksort ($fruits);reset ($fruits);while (list ($key, $val) = each ($fruits)) { echo "$key = $val\n";}
This example would display:
a = orangeb = bananac = appled = lemon
在多維陣列中排序
自行定義物件比較大小的方式，把多維陣列當作物件的一維陣列排序 自行定義物件比較大小的函式，傳入參數：兩個物件，傳回
值： =0 兩個物件相等 >0 第一個物件比較大 <0 第二個物件比較大
void usort ( array array, callback cmp_function) Sort an array by values using a user-defined comparison
function 逆向使用者自訂排序 kusort()
function cmp ($a, $b) { if ($a == $b) return 0; return ($a > $b) ? -1 : 1;}$a = array (3, 2, 5, 6, 1);usort ($a, "cmp");while (list ($key, $value) = each ($a)) { echo "$key: $value\n";}
function cmp ($a, $b) { if ($a == $b) return 0; return ($a > $b) ? -1 : 1;}$a = array (3, 2, 5, 6, 1);usort ($a, "cmp");while (list ($key, $value) = each ($a)) { echo "$key: $value\n";}
This example would display:
0: 61: 52: 33: 24: 1
This example would display:
0: 61: 52: 33: 24: 1
對陣列重新排序
shuffle() 亂排 This function shuffles (randomizes the order of the
elements in) an array. You must use srand() to seed this function.
Example: http://w3.im.knu.edu.tw/~annie/chapter03/bobs_front_page.php
相反的順序
array_reverse -- Return an array with elements in reverse order array array_reverse ( array array [, bool preserve_keys])
array_reverse() takes input array and returns a new array with the order of the elements reversed, preserving the keys if preserve_keys is TRUE.
$input = array ("php", 4.0, array ("green", "red"));$result = array_reverse ($input);$result_keyed = array_reverse ($input, TRUE);
$input = array ("php", 4.0, array ("green", "red"));$result = array_reverse ($input);$result_keyed = array_reverse ($input, TRUE);
This makes both $result and $result_keyed have the same elements, but note the difference between the keys. The printout of $result and $result_keyed will be:
This makes both $result and $result_keyed have the same elements, but note the difference between the keys. The printout of $result and $result_keyed will be:
Array( [0] => Array ( [0] => green [1] => red )
[1] => 4 [2] => php)Array( [2] => Array ( [0] => green [1] => red )
[1] => 4 [0] => php)
Array( [0] => Array ( [0] => green [1] => red )
[1] => 4 [2] => php)Array( [2] => Array ( [0] => green [1] => red )
[1] => 4 [0] => php)
由檔案載入陣列範例： vieworders.php file -- Reads entire file into an array
array file ( string filename [, int use_include_path [, resource context]])
Identical to readfile(), except that file() returns the file in an array. Each element of the array corresponds to a line in the file, with the newline still attached. Upon failure, file() returns FALSE.
由檔案載入陣列範例： vieworders2.php explode -- Split a string by string
array explode ( string separator, string string [, int limit]) Returns an array of strings, each of which is a substring of
string formed by splitting it on boundaries formed by the string separator. If limit is set, the returned array will contain a maximum of limit elements with the last element containing the rest of string.
If separator is an empty string (""), explode() will return FALSE. If separator contains a value that is not contained in string, then explode() will return an array containing string.
intval -- Get integer value of a variable int intval ( mixed var [, int base])
其他陣列操作
each() -- Return the current key and value pair from an array and advance the array cursor
next() -- Advance the internal array pointer of an array
prev() -- Rewind the internal array pointer current() -- Return the current element in an array end() -- Set the internal pointer of an array to its last
element reset() -- Set the internal pointer of an array to its
first element
對陣列中每一個元素逐一進行運算
array_walk -- Apply a user function to every member of an array int array_walk ( array array, callback function [,
mixed userdata])
<?php$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");function test_alter (&$item1, $key, $prefix) { $item1 = "$prefix: $item1";}function test_print ($item2, $key) { echo "$key. $item2<br>\n";}echo "Before ...:\n";array_walk ($fruits, 'test_print');array_walk ($fruits, 'test_alter', 'fruit');echo "... and after:\n";array_walk ($fruits, 'test_print');?>
<?php$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");function test_alter (&$item1, $key, $prefix) { $item1 = "$prefix: $item1";}function test_print ($item2, $key) { echo "$key. $item2<br>\n";}echo "Before ...:\n";array_walk ($fruits, 'test_print');array_walk ($fruits, 'test_alter', 'fruit');echo "... and after:\n";array_walk ($fruits, 'test_print');?>
The printout of the program above will be:
Before ...:d. lemona. orangeb. bananac. apple... and after:d. fruit: lemona. fruit: orangeb. fruit: bananac. fruit: apple
The printout of the program above will be:
Before ...:d. lemona. orangeb. bananac. apple... and after:d. fruit: lemona. fruit: orangeb. fruit: bananac. fruit: apple
計算陣列元素個數 count -- Count elements in a variable
int count ( mixed var) Returns the number of elements in var, which is typically an
array (since anything else will have one element). If var is not an array, 1 will be returned (exception:
count(NULL) equals 0). sizeof -- Alias of count() array_count_values -- Counts all the values of an
array array array_count_values ( array input) array_count_values() returns an array using the values of
the input array as keys and their frequency in input as values.
將陣列轉純量變數 extract -- Import variables into the current symbol
table from an array int extract ( array var_array [, int extract_type [, string
prefix]]) This function is used to import variables from an array into
the current symbol table. It takes an associative array var_array and treats keys as variable names and values as variable values. For each key/value pair it will create a variable in the current symbol table, subject to extract_type and prefix parameters.
extract() checks each key to see whether it has a valid variable name. It also checks for collisions with existing variables in the symbol table. The way invalid/numeric keys and collisions are treated is determined by the extract_type. It can be one of the following values:
將陣列轉純量變數 EXTR_OVERWRITE （ default ）
If there is a collision, overwrite the existing variable. EXTR_SKIP
If there is a collision, don't overwrite the existing variable. EXTR_PREFIX_SAME
If there is a collision, prefix the variable name with prefix. EXTR_PREFIX_ALL
Prefix all variable names with prefix. Beginning with PHP 4.0.5, this includes numeric variables as well.
EXTR_PREFIX_INVALID Only prefix invalid/numeric variable names with prefix. This flag was added in PHP 4.0.5.
EXTR_IF_EXISTS Only overwrite the variable if it already exists in the current symbol table, otherwise do nothing. This
is useful for defining a list of valid variables and then extracting only those variables you have defined out of $_REQUEST, for example. This flag was added in PHP 4.2.0.
EXTR_PREFIX_IF_EXISTS Only create prefixed variable names if the non-prefixed version of the same variable exists in the
current symbol table. This flag was added in PHP 4.2.0. EXTR_REFS
Extracts variables as references. This effectively means that the values of the imported variables are still referencing the values of the var_array parameter. You can use this flag on its own or combine it with any other flag by OR'ing the extract_type. This flag was added in PHP 4.3.0.
