How to write data into an array in php

PHP is a widely used open source scripting language that is used in many fields such as web programming, server-side programming, and command line tools. In PHP programming, sometimes you need to save some data into an array for processing and manipulation, so this article will introduce how to write data into a PHP array.

1. Basic array definition

PHP array is an efficient data structure that can save multiple key-value pairs. Using arrays in PHP is very simple: you can create an empty array through the array() function, or you can assign an initial value to the array when you create it. For example:

// 创建空数组
$my_array = array();

// 创建含有三个元素的数组
$my_array = array("apple", "banana", "orange");

This creates an array with three elements. In this array, "apple" is the first element with the key name 0, "banana" is the second element with the key name 1, and "orange" is the third element with the key name 2. We can access the elements in the array using the array name and key name.

2. Write data into an array

Sometimes you need to save some data into an array. In this case, you can use PHP's array function to achieve this. Commonly used array functions include: array_push(), array_unshift(), $array[], $array[key], etc.

1. Use the array_push() function to add elements

The array_push() function can add one or more elements to the end of the array and return the number of added elements. For example:

$my_array = array();
array_push($my_array, "apple", "banana", "orange");

In this way, "apple", "banana" and "orange" are added to the array $my_array respectively.

2. Use the array_unshift() function to add elements

Unlike array_push(), the array_unshift() function adds one or more elements to the beginning of the array. For example:

$my_array = array("apple", "banana");
array_unshift($my_array, "orange");

This will insert "orange" at the beginning of the $my_array array.

3. Use the $array[] syntax to add elements

When creating an array, if you use the $array[] assignment syntax, you can easily add new elements to the array. For example:

$my_array = array();
$my_array[] = "apple";
$my_array[] = "banana";
$my_array[] = "orange";

In this way, "apple", "banana" and "orange" are added to the $my_array array respectively.

4. Use the $array[key] syntax to add elements

If you want to add an element at a specified position in the array, you can use the $array[key] assignment syntax to complete. For example:

$my_array = array("apple", "orange");
$my_array[1] = "banana";

This will change the element with key name 1 in the $my_array array from "orange" to "banana".

3. Summary

The above are several methods of adding elements to an array. The usage methods are different, and you can choose according to the situation. Arrays are a very basic and important data structure in PHP. Mastering the usage of arrays will help you write efficient and maintainable PHP applications.

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