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What is the function to synthesize arrays in php

青灯夜游
青灯夜游Original
2022-06-28 16:59:362660browse

There are three array composition functions: 1. array_combine(), which creates a new array by merging two arrays. The syntax is "array_combine (key name array, key value array)"; 2. array_merge(), which can To merge multiple arrays into one array, the syntax is "array_merge(array1,array2...)"; 3. array_merge_recursive(), which can merge multiple arrays into one array. The element key names will not be overwritten if they are the same. form subarrays.

What is the function to synthesize arrays in php

The operating environment of this tutorial: Windows 7 system, PHP version 8.1, DELL G3 computer

php provides 3 pairs of arrays for synthesis Function:

  • array_combine()

  • array_merge()

  • array_merge_recursive()

1. Use array_combine() to synthesize arrays

array_combine() function creates a new array by merging two arrays, one of which is an array element. is the key name, and the elements of the other array are the key values.

array_combine(keys,values);
Parameters Description
keys Required . Specifies the key name of the array.
values Required. Specifies the key value of the array.

Note: The number of elements in the key name array and the key value array must be the same!

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$name=array("Peter","Ben","Joe");
$age=array("35","37","43");
var_dump($name);
var_dump($age);
$arr=array_combine($name,$age);
var_dump($arr);
?>

What is the function to synthesize arrays in php

2. Use the array_merge() function to synthesize an array

array_merge( ) function is used to combine one or more arrays into a single array.

Tip: You can input one or more arrays to the function.

array_merge(array1,array2,array3...)
Parameters Description
array1 Required . Specifies an array.
array2 Optional. Specifies an array.
array3 Optional. Specifies an array.

Note: If two or more array elements have the same key name, the last element will overwrite the other elements.

Note: If you only input an array to the array_merge() function, and the keys are integers, the function will return a new array with integer keys, with keys re-indexed starting at 0 ( See Example 1 below).

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$a1=array("a"=>"red","b"=>"green");
$a2=array("c"=>"blue","b"=>"yellow");
var_dump(array_merge($a1,$a2));
?>

What is the function to synthesize arrays in php

3. Use array_merge_recursive() function

array_merge_recursive() function Used to combine one or more arrays into one array.

array_merge_recursive(array1,array2,array3...)

Explanation: The difference between the array_merge_recursive() function and the array_merge() function is to handle the situation where two or more array elements have the same key name. array_merge_recursive() does not perform key name overwriting, but recursively combines multiple values ​​with the same key name into an array.

Note: If you just input an array to the array_merge_recursive() function, the result is the same as array_merge(), the function will return a new array with integer keys, with keys starting at 0 for re-indexing.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$a1=array("a"=>"red","b"=>"green");
$a2=array("c"=>"blue","b"=>"yellow");
var_dump(array_merge_recursive($a1,$a2));
?>

What is the function to synthesize arrays in php

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