近期又开始修改wp-cms了,下面记录的是关于php中foreach()循环的用法

foreach()共有两种用法:
1.
Source code    
foreach(array_name as $value)   {      statement;   }

这里的array_name是要遍历的数组名,每次循环中,array_name数组的当前元素的值被赋给$value,并且数组内部的下标向下移一步,也就是下次循环回得到下一个元素。
2.

Source code    
foreach(array_name as $key => $value)   {       statement;    }

这里跟第一种方法的区别就是多了个$key,也就是除了把当前元素的值赋给$value外,当前元素的键值也会在每次循环中被赋给变量$key。键值可以是下标值,也可以是字符串。比如book[0]=1中的“0”,book[id]=”001″中的“id”
范用法的更多例子:
Source code    
<?php/*-------------------------------------------------------------------------*//* foreach example 1: value only */echo "foreach example 1: value only "."<br />"; $a = array(1, 2, 3, 17); foreach ($a as $v) {   echo "Current value of "$a: $v"."<br />";} /*-------------------------------------------------------------------------*//* foreach example 2: value (with key printed for illustration) */echo "<br />"."<br />"."foreach example 2: value (with key printed for illustration) "."<br />"; $a = array(1, 2, 3, 17); $i = 0; /* for illustrative purposes only */ foreach ($a as $v) {    echo ""$a[$i] => $v"."<br />";    $i++;} /*-------------------------------------------------------------------------*//* foreach example 3: key and value */echo  "<br />"."<br />"."foreach example 3: key and value "."<br />"; $a = array(    "one" => 1,    "two" => 2,    "three" => 3,    "seventeen" => 17); foreach ($a as $k => $v) {    echo ""$a[$k] => $v"."<br />";} /*-------------------------------------------------------------------------*//* foreach example 4: multi-dimensional arrays */echo "<br />"."<br />"."foreach example 4: multi-dimensional arrays "."<br />";$a = array();$a[0][0] = "a";$a[0][1] = "b";$a[1][0] = "y";$a[1][1] = "z"; foreach ($a as $v1) {    foreach ($v1 as $v2) {        echo "$v2"n";    }} /*-------------------------------------------------------------------------*//* foreach example 5: dynamic arrays */echo "<br />"."<br />"."foreach example 5: dynamic arrays "."<br />"; foreach (array(1, 2, 3, 4, 5) as $v) {    echo "$v"n";}?>

结果如下:

Source code    
foreach example 1: value onlyCurrent value of $a: 1Current value of $a: 2Current value of $a: 3Current value of $a: 17 foreach example 2: value (with key printed for illustration)$a[0] => 1$a[1] => 2$a[2] => 3$a[3] => 17 foreach example 3: key and value$a[one] => 1$a[two] => 2$a[three] => 3$a[seventeen] => 17 foreach example 4: multi-dimensional arraysa b y z foreach example 5: dynamic arrays1 2 3 4 5

关于php中foreach()循环的用法

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