特殊排列顺序

Question

请你能帮助我：

我有一个数组排序的关键：

$a['a'] = value; 
$a['b'] = value; 
$a['c'] = value; 
$a['d'] = value; 
$a['e'] = value; 

我需要通过这个规则reordeer此 - 举一个领域，把它放在第一个地方，另一个不改变

fe

$a['c'] = value; 
$a['a'] = value; 
$a['b'] = value; 
$a['d'] = value; 
$a['e'] = value; 

或

$a['d'] = value; 
$a['a'] = value; 
$a['b'] = value; 
$a['c'] = value; 
$a['e'] = value; 

Answer 1

我认为你的意思是这样的：

function get_and_place_first($index, $array) { 
    $new_first_element = $array[$index];  // save element you want to have as first 
    unset($array[$index]);      // delete that element from old position 
    array_unshift($array, $new_first_element); // place it at the beginning of $array 
} 

你应该这样使用它：

get_and_place_first('c', $a); 

，你应该从你的第一个例子预期的效果。当然你可能想要检查给定数组中是否存在元素等，但这取决于你。

Answer 2

试试从http://ykyuen.wordpress.com/2011/09/16/php-swap-array-elements-by-array-keys/

function array_swap_assoc($key1, $key2, $array) { 
    $newArray = array(); 
    foreach ($array as $key => $value) { 
    if ($key == $key1) { 
     $newArray[$key2] = $array[$key2]; 
    } elseif ($key == $key2) { 
     $newArray[$key1] = $array[$key1]; 
    } else { 
     $newArray[$key] = $value; 
    } 
    } 
    return $newArray; 
} 

代码示例这个功能：

<?php 
    $temp = array('a' => 'A', 'b' => 'B'); 
    $temp = array_swap_assoc('a', 'b', $temp); 
    print_r($temp); 
?>