How to modify the key value of an array in php

As a popular server-side scripting language, PHP can help develop Web-oriented software and websites. It supports many data types, one of which is array. An array is an ordered set of values, each of which can be identified by a key. In some cases, we may need to modify the key value of the array. This article will introduce how to modify the key value of the array in PHP.

1. Regenerate an array with new key names through the array_combine() function

This is one of the simplest methods. You can use the array_combine() function to regenerate an array with new keys. array of names. The array_combine() function can accept two arrays as parameters, one as the new key array and the other as the new value array. Both arrays must contain the same number of elements.

Sample code:

//原数组
$oldArr = array("apple"=>"苹果", "banana"=>"香蕉", "orange"=>"橘子");
//新数组，使用range()函数生成1～3的数组
$newKeysArr = range(1, 3);
//重新组合数组
$newArr = array_combine($newKeysArr, $oldArr);

In this example, we use the range() function to generate a numeric array of 1~3 as a new key array, and then use the array_combine() function to The new array is combined with the old array to generate a new array with new key names.

2. Use a foreach loop to generate a new array

This method is relatively more flexible, and it allows us to rewrite the key name of each element. We do this by looping through the array.

Sample code:

//原数组
$oldArr = array("apple"=>"苹果", "banana"=>"香蕉", "orange"=>"橘子");
//新数组
$newArr = array();
//遍历数组，使用新键名重写每个元素
foreach($oldArr as $oldKey=>$oldValue) {
    $newArr[$oldKey . "_suffix"] = $oldValue;
}

In this example, we use a foreach loop to iterate through the old array and rewrite each element with a new key name. This new key name is the original key name plus a suffix. The disadvantage of this method is that it requires manually writing loops and new key names, but it allows us to operate array elements more flexibly.

3. Use array_map() function and anonymous function

In this method, we will use array_map() function to apply an anonymous function that passes elements for conversion. In the anonymous function we can Modify the key name of each element.

Sample code:

//原数组
$oldArr = array("apple"=>"苹果", "banana"=>"香蕉", "orange"=>"橘子");
//匿名函数，使用新的键名更新每个元素
$newArr = array_map(function($value) {
    $newKey = $value . "_suffix";
    return array($newKey => $value);
}, $oldArr);
//合并新数组
$newArr = call_user_func_array('array_merge', $newArr);

In this example, we use an anonymous function to apply the new key name to each element. In the anonymous function, we replace the original key of each element with a new key and generate a new array with the new key and the old value.

Finally use the array_merge() function to merge all new array elements. The disadvantage of this method is that it may not be easy to understand, but using it allows us to manipulate array elements more concisely.

Summary:

This article introduces three methods to modify the key names of PHP arrays. With these methods, we can manipulate array elements more flexibly to suit our needs. In actual development, we should choose the most suitable method according to needs.

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