What are the functions for appending array elements in php?

4 kinds of append functions: 1. array_push(), syntax "array_push(array, element value list...)"; 2. array_merge(), syntax "array_merge(array 1, array 2...)" "; 3. array_merge_recursive(), etc.

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

The so-called appending array elements means adding them to the end of the array Add elements. PHP has a variety of built-in functions for appending array elements, which are introduced below.

1. array_push() function

array_push() function can insert one or more elements (key values) at the end of the array. The syntax is as follows:

array_push($array,$value1,$value2...)

Example:

<?php
$arr=array(1,2,3);
array_push($arr,8,"9",3.14);
var_dump($arr);
?>

2. array_merge() function

array_merge() function is used to merge an Or multiple arrays are combined into one array

array_merge(array1,array2,array3...)

• will store the values ​​of array2, array3... into array1.

Note: When a key in an input array already exists in the result array, array_merge() will overwrite the previously existing key/value pair and replace it with the current input Key/value pairs in an array.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array(10,12,20);
$result =array_merge($arr,array(2,3,4)) ;
var_dump($result);
?>

3. array_merge_recursive() function

array_merge_recursive() function and array_merge above () are the same and can combine two or more arrays together to form a combined array.

The difference is: when the same key name exists, array_merge() will overwrite the previously existing key/value pair, while array_merge_recursive() will merge the two values ​​together to form a new array, with the original Some keys are used as array names, and there is also a form of array merging, which is to recursively append arrays.

Syntax:

array_merge_recursive(array array1,array array2[…,array arrayN])

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$arr=array(10,12,20);
$result =array_merge_recursive($arr,array(2,3,4,8)) ;
var_dump($result);
?>

4, array_splice() function

The array_splice() function is a powerful function that can be used to delete array elements, replace array elements, and also insert array elements (just set the parameter $length to 0). Syntax:

array_splice($array,$start,$length,$value)

• When $length=0, then the parameter $start can specify the position (subscript) to start inserting

• Parameter$ value can specify the insertion value (if there are multiple values, it needs to be set as an array).

• When the value of $start is set to the "array length value", that is, count($arr) can insert elements at the end of the array.

<?php
$arr=array(1,2,3);
array_splice($arr,count($arr),0,"1");
var_dump($arr);

array_splice($arr,count($arr),0,array(25,"3"));
var_dump($arr);
?>

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