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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.
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); ?>
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)); ?>
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)); ?>
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