What are the php array replacement functions?

php array replacement functions include: 1. array_replace() function, which uses the value of the following array to replace the value of the first array; 2. array_replace_recursive() function, which recursively uses the value of the following array to replace the first one. The value of the array; 3. array_splice() function.

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

1.array_replace() function

array_replace() function replaces the value of the first array with the value of the subsequent array. The syntax is as follows:

array_replace(array1,array2,array3...)

• If a key exists in the first array array1 and also exists in the second array array2, the value in the first array array1 will be replaced by the second array Replace the values ​​in array2.

• If a key only exists in the first array array1, it will remain unchanged.

• If a key exists in the second array array2, but does not exist in the first array array1, the element will be created in the first array array1.

• If multiple replacement arrays are passed, they will be processed in order, and the values ​​of the subsequent arrays will overwrite the values ​​of the previous arrays.

Example 1: If a key exists in array1 and also exists in array2, the value of the first array will be replaced by the value of the second array

<?php
$a1=array("a"=>"red","b"=>"green");
$a2=array("a"=>"orange","burgundy");
print_r(array_replace($a1,$a2));
?>

Output:

Array ( [a] => orange [b] => green [0] => burgundy )

Example 2: If a key only exists in the second array:

<?php
$a1=array("a"=>"red","green");
$a2=array("a"=>"orange","b"=>"burgundy");
print_r(array_replace($a1,$a2));
?>

Output:

Array ( [a] => orange [0] => green [b] => burgundy )

2, array_replace_recursive() function

array_replace_recursive() function recursively replaces the value of the first array with the value of the subsequent array. The syntax is as follows:

array_replace_recursive(array1,array2,array3...)

Example: Multiple arrays

<?php
$a1=array("a"=>array("red"),"b"=>array("green","blue"));
$a2=array("a"=>array("yellow"),"b"=>array("black"));
$a3=array("a"=>array("orange"),"b"=>array("burgundy"));
print_r(array_replace_recursive($a1,$a2,$a3));
?>

Output:

Array ( [a] => Array ( [0] => orange ) [b] => Array ( [0] => burgundy [1] => blue ) )

Explanation: The difference between array_replace() and array_replace_recursive():

<?php
$a1=array("a"=>array("red"),"b"=>array("green","blue"),);
$a2=array("a"=>array("yellow"),"b"=>array("black"));

$result=array_replace_recursive($a1,$a2);
print_r($result);

$result=array_replace($a1,$a2);
print_r($result);
?>

Output:

Array ( [a] => Array ( [0] => yellow ) [b] => Array ( [0] => black [1] => blue ) ) 
Array ( [a] => Array ( [0] => yellow ) [b] => Array ( [0] => black ) )

3. array_splice() function

array_splice() function removes the selected element from the array and replaces it with the new element replace it. This function will also return the array containing the removed elements. If the function does not remove any elements (length=0), the replaced array will be inserted from the position of the start parameter.

Syntax

array_splice(array,start,length,array)

Example: Set the length parameter to 0:

<?php
$a1=array("0"=>"red","1"=>"green");
$a2=array("0"=>"purple","1"=>"orange");
array_splice($a1,1,0,$a2);
print_r($a1);
?>

Output:

Array ( [0] => red [1] => purple [2] => orange [3] => green )

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