Replace array php

In PHP, replacing an array is a very important operation, which allows programmers to modify and process data in the array more conveniently. This article will introduce the relevant knowledge and implementation methods of array replacement in PHP.

1. What is array replacement?

Array replacement refers to replacing certain elements in an array with other elements, or replacing the entire array with another array. In PHP, we can implement array replacement operations through some built-in functions, such as array_replace, array_replace_recursive, etc.

2. array_replace function

The array_replace function is one of the functions that implements array replacement in PHP. Its function is to replace the elements of one array with the elements of another array. If the original array has the same key name, the value of the original array will be overwritten with the value of the replacement array.

The following is the syntax of the array_replace function:

mixed array_replace ( array $array1 , array $array2 [, array $... ] )

Among them, $array1 is the array to be replaced, $array2 is the value of the corresponding key name in the replacement array 1, and there can also be multiple replacements. array.

The example is as follows:

$array1 = array("name"=>"Tom", "age"=>20, "sex"=>"male");
$array2 = array("name"=>"John", "age"=>25);
$result = array_replace($array1, $array2);
print_r($result);

Output result:

Array
(
    [name] => John
    [age] => 25
    [sex] => male
)

As you can see, the values ​​corresponding to the "name" and "age" key names in $array2 have replaced $array1 The "sex" key name does not appear in $array2, so the original value is retained.

3. array_replace_recursive function

The array_replace_recursive function has a similar function to the array_replace function, both are used to replace array elements. The difference is that the array_replace_recursive function can not only replace the value of one level element in the array, but also replace the value of multi-level elements (multidimensional array).

The following is the syntax of the array_replace_recursive function:

mixed array_replace_recursive ( array $array1 , array $array2 [, array $... ] )

The example is as follows:

$array1 = array("name"=>"Tom", "age"=>20, "address"=>array("city"=>"Beijing", "province"=>"Hebei"));
$array2 = array("name"=>"John", "address"=>array("city"=>"Shanghai"));
$result = array_replace_recursive($array1, $array2);
print_r($result);

Output result:

Array
(
    [name] => John
    [age] => 20
    [address] => Array
        (
            [city] => Shanghai
            [province] => Hebei
        )

)

As you can see, the "name in $array2 "The value corresponding to the key name replaces the value in $array1, and the array corresponding to the "address" key name is recursively replaced, and the replacement result is finally output.

4. array_merge function

In addition to the above two functions, there is also an array_merge function that can also implement array replacement. Its function is to merge two or more arrays into one array, and elements with the same key name will be overwritten by the subsequent array.

The following is the syntax of the array_merge function:

array array_merge ( array $array1 [, array $... ] )

The example is as follows:

$array1 = array("name"=>"Tom", "age"=>20, "sex"=>"male");
$array2 = array("name"=>"John", "age"=>25);
$result = array_merge($array1, $array2);
print_r($result);

Output result:

Array
(
    [name] => John
    [age] => 25
    [sex] => male
)

As you can see, the "name in $array2 "The value corresponding to the "age" key name replaces the value in $array1, while the "sex" key name retains the original value.

5. Summary

Array replacement is a very common operation in PHP, which allows programmers to modify and process data in the array more conveniently. This article introduces three functions in PHP that implement array replacement: array_replace, array_replace_recursive, and array_merge. They can all implement the array replacement function very well. When using it, you need to choose different functions according to the actual situation, and you need to pay attention to whether the overwriting problem needs to be dealt with in subsequent operations.

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