How to add elements at the beginning of an array using array_unshift() function in PHP

How to use the array_unshift() function in PHP to add elements at the beginning of the array

In PHP, we often need to add, delete, modify and other operations to the array. And if we need to add one or more elements to the beginning of the array, we can use the array_unshift() function provided by PHP.

The array_unshift() function will insert the passed element into the beginning of the array and return the new array length. The elements in the original array will be moved backward according to the number of inserted elements. Let's look at some specific code examples:

Example 1: Add an element at the beginning of the array

<?php

$colors = array("红色", "蓝色", "绿色");

// 使用array_unshift()函数在数组开头添加一个元素
array_unshift($colors, "黄色");


print_r($colors);

?>

Output result:

Array
(
    [0] => 黄色
    [1] => 红色
    [2] => 蓝色
    [3] => 绿色
)

Example 2: Add multiple elements at the beginning of the array elements

<?php

$fruits = array("苹果", "香蕉", "橙子");

// 使用array_unshift()函数在数组开头添加多个元素
array_unshift($fruits, "葡萄", "樱桃");


print_r($fruits);

?>

Output result:

Array
(
    [0] => 葡萄
    [1] => 樱桃
    [2] => 苹果
    [3] => 香蕉
    [4] => 橙子
)

As you can see from the above example, we can easily add one or more elements at the beginning of the array through the array_unshift() function. It should be noted that the added elements can be of any data type, including strings, integers, floating point numbers, arrays, etc.

In addition to adding elements at the beginning of the array, we can also use other PHP array functions to operate arrays. For example, the array_push() function can add elements at the end of the array, the array_shift() function can remove elements at the beginning of the array, etc. .

Summary
Using the array_unshift() function in PHP can add elements to the beginning of the array, which is very convenient and practical. Through code examples, we can see the usage and effects of the array_unshift() function. In actual development, we can flexibly use this function according to needs to improve the readability and efficiency of the code.

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