PHP 遍歷數(shù)組語(yǔ)句總結(jié)(foreach,for,list,each)

2024-05-04 23:13:45

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在php中遍歷循環(huán)讀出數(shù)組的方法有幾種，foreach,for,list,each,while都是可以的，只是那種更適合用來(lái)遍歷數(shù)組了。
foreach來(lái)訪問(wèn), 遍歷的順序是固定的么? 以什么順序遍歷呢?

比如:

代碼如下

<?php
$colors= array('red','blue','green','yellow');
foreach ($colors as $color){
//add your codes
}
?>

例2

$capitals= array("Ohio"=> "Columbus","Towa"=> "Des Moines","Arizona"=> "Phoenix");
foreach($capitals as $key=> $val){
//add your codes
}

while()

while() 通常和 list()，each()配合使用。

#example2:

代碼如下

<?php
$colors = array('red','blue','green','yellow');

while(list($key,$val) = each($colors)) {
echo "Other list of $val. ";
}
?>

顯示結(jié)果：

Other list of red.
Other list of blue.
Other list of green.
Other list of yellow.

3. for()
#example3:

代碼如下

<?php
$arr = array ("0" => "zero","1" => "one","2" => "two");

for ($i = 0;$i < count($arr); $i++) {
$str = $arr[$i];
echo "the number is $str. ";
}
?>
顯示結(jié)果：

the number is zero.
the number is one.
the number is two.

========= 以下是函數(shù)介紹 ==========

key()
mixed key(array input_array)

key()函數(shù)返回input_array中位于當(dāng)前指針位置的鍵元素。

#example4

代碼如下

<?php
$capitals = array("Ohio" => "Columbus","Towa" => "Des Moines","Arizona" => "Phoenix");
echo "Can you name the capitals of these states?";
while($key = key($capitals)) {
echo $key." ";
next($capitals);
//每個(gè)key()調(diào)用不會(huì)推進(jìn)指針。為此要使用next()函數(shù)
}
?>

Can you name the capitals of these states?
Ohio
Towa
Arizona

each() 函數(shù)遍歷數(shù)組

例子 1

代碼如下

<?php
$people = array("Peter", "Joe", "Glenn", "Cleveland");
print_r (each($people));
?>

輸出：

Array ( [1] => Peter [value] => Peter [0] => 0 [key] => 0 )

子 2
each() 經(jīng)常和 list() 結(jié)合使用來(lái)遍歷數(shù)組。本例與上例類似，不過(guò)循環(huán)輸出了整個(gè)數(shù)組：

代碼如下

復(fù)制代碼

<?php
$people = array("Peter", "Joe", "Glenn", "Cleveland");

reset($people);

while (list($key, $val) = each($people))
{
echo "$key => $val ";
}
?>

輸出：

0 => Peter
1 => Joe
2 => Glenn
3 => Cleveland

多維數(shù)組的遞歸遍歷

代碼如下

<?php
/*
* -------------------------------------------------
* Author :
* Url : www.45it.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.' ';
}
}
}

$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);
?>

結(jié)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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