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 程式師世界 >> 編程語言 >> 網頁編程 >> PHP編程 >> 關於PHP編程 >> PHP 遍歷數組語句總結(foreach,for,list,each)

PHP 遍歷數組語句總結(foreach,for,list,each)

編輯:關於PHP編程

     foreach來訪問, 遍歷的順序是固定的麼? 以什麼順序遍歷呢?

    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.<br />";
    }
    ?>

    顯示結果:

    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.<br />";
    }
    ?>
    顯示結果:

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

     

    ========= 以下是函數介紹 ==========

    key()
    mixed key(array input_array)

    key()函數返回input_array中位於當前指針位置的鍵元素。

    #example4

    代碼如下


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

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

     

    each() 函數遍歷數組

    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() 經常和 list() 結合使用來遍歷數組。本例與上例類似,不過循環輸出了整個數組:

    代碼如下

    復制代碼

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

    reset($people);

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

     

    輸出:

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


    多維數組的遞歸遍歷

    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.'<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);
    ?>

    結果

    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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