PHP 遍历数组语句总结(foreach,for,list,each)
在php中遍历循环读出数组的方法有几种,foreach,for,list,each,while都是可以的,只是那种更适合用来遍历数组了。
foreach来访问,遍历的顺序是固定的么? 以什么顺序遍历呢?
比如:代码如下:
<?php
$colors= array('red','blue','green','yellow');
foreach ($colors as $color) {
//add your codes
}
?>例2,代码如下:
<?php
$capitals = array(
"Ohio" => "Columbus",
"Towa" => "Des Moines",
"Arizona" => "Phoenix"
);
foreach ($capitals as $key => $val) {
//add your codes
}
?>while()
while() 通常和 list(),each()配合使用,实例代码如下:
<?php
$colors = array(
'red',
'blue',
'green',
'yellow'
);
while (list($key, $val) = each($colors)) {
echo "Other list of $val.<br />";
}
/*
显示结果:
Other list of red.
Other list of blue.
Other list of green.
Other list of yellow.
*/
?>3. for(),实例代码如下:
<?php
$arr = array(
"0" => "zero",
"1" => "one",
"2" => "two"
);
for ($i = 0; $i < count($arr); $i++) {
$str = $arr[$i];
echo "the number is $str.<br />";
}
/*
显示结果:
the number is zero.
the number is one.
the number is two.
*/
?>以下是函数介绍:
key()
mixed key(array input_array)
key()函数返回input_array中位于当前指针位置的键元素。
实例代码如下:
<?php
$capitals = array(
"Ohio" => "Columbus",
"Towa" => "Des Moines",
"Arizona" => "Phoenix"
);
echo "<p>Can you name the capitals of these states?</p>";
while ($key = key($capitals)) {
echo $key . "<br />";
next($capitals);
//每个key()调用不会推进指针。为此要使用next()函数
}
/*结果如下
Can you name the capitals of these states?
Ohio
Towa
Arizona
*/
?>each() 函数遍历数组
例子1,代码如下:
<?php $people = array( "Peter", "Joe", "Glenn", "Cleveland" ); print_r(each($people)); //输出: //Array ( [1] => Peter [value] => Peter [0] => 0 [key] => 0 ) ?>
例子2,代码如下:
each() 经常和 list() 结合使用来遍历数组,本例与上例类似,不过循环输出了整个数组,代码如下:
<?php
$people = array(
"Peter",
"Joe",
"Glenn",
"Cleveland"
);
reset($people);
while (list($key, $val) = each($people)) {
echo "$key => $val<br />";
}
/*
输出:
0 => Peter
1 => Joe
2 => Glenn
3 => Cleveland
*/
?>多维数组的递归遍历,代码如下:
<?php
/*
* -------------------------------------------------
* Author :
* Url : www.phprm.com* Date : 2011-03-09
* -------------------------------------------------
*/
function arr_foreach($arr) {
if (!is_array($arr)) {
return false;
}
foreach ($arr as $key => $val) {
if (is_array($val)) {
arr_foreach($val);
} else {
echo $val . '<br/>';
}
}
}
$arr1 = array (1=>array(11,12,13,14=>array(141,142)),2,3,4,5);
echo '<pre>';
print_r($arr1);
echo '<pre>';
arr_foreach($arr1);
/*
结果
Array
(
[1] => Array
(
[0] => 11
[1] => 12
[2] => 13
[14] => Array
(
[0] => 141
[1] => 142
)
)
[2] => 2
[3] => 3
[4] => 4
[5] => 5
)
11
12
13
141
142
2
3
4
5
*/
?>
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