Add a pair of values ​​to the php array

PHP is a powerful server-side scripting language that is widely used in Web development and is one of the main tools for modern Web development. In PHP, array is a commonly used and important data structure. PHP arrays are powerful features that can store multiple values ​​and are used for various programming tasks.

In PHP, adding a key/value pair to an array is a common operation. This article will introduce methods and techniques for adding a pair of values ​​​​in a PHP array.

1. Use the array subscript operator

In PHP, an array is an ordered set of key/value pairs. To add an element to an array, you first need to create an array element with the specified key. You can use the array subscript operator [] to add elements to an array, for example:

$arr = array();
$arr['key1'] = 'value1';

In this example, we create an empty array and then use the array subscript operator to add a key-value pair into the array. The key is "key1" and the value is "value1".

2. Use the array_push function

If you need to add one or more elements to the end of the array, you can use the array_push() function. This function adds one or more values ​​to the end of the array and returns the length of the new array. For example:

$arr = array('value1', 'value2');
array_push($arr, 'value3', 'value4');

In this example, we create an array with two elements and then add two elements to the array using the array_push() function. The new array contains 4 elements. Please note that the array_push() function can only add elements to the end of the array.

3. Use key names to assign values

Another way to add a pair of values ​​to a PHP array is to use key names to assign values. This method does not use the array subscript operator [] or the array_push() function. It works for adding new key/value pairs to an already existing array. For example:

$arr = array('key1'=>'value1', 'key2'=>'value2');
$arr['key3'] = 'value3';

In this example, we create an array containing two key-value pairs. We then add the new key/value pair to the array using the array subscript operator []. The key name is "key3" and the value is "value3".

4. Use the " " operator

Another way to add elements to an array is to use the " " operator. This method merges two arrays into one array and adds new elements. For example:

$arr1 = array('key1'=>'value1', 'key2'=>'value2');
$arr2 = array('key3'=>'value3', 'key4'=>'value4');
$arr3 = $arr1 + $arr2;

In this example, we create two arrays $arr1 and $arr2 and then merge them into a new array $arr3 using the " " operator. The new array contains 4 key-value pairs. If both arrays contain the same keys, the key/value pairs in $arr2 will overwrite the key/value pairs in $arr1.

5. Use the array_merge function

If you need to merge multiple arrays into one array, you can use the array_merge() function. This function combines multiple arrays into a new array and returns the new array. For example:

$arr1 = array('key1'=>'value1', 'key2'=>'value2');
$arr2 = array('key3'=>'value3', 'key4'=>'value4');
$arr3 = array('key5'=>'value5', 'key6'=>'value6');
$arr4 = array_merge($arr1, $arr2, $arr3);

In this example, we created three arrays $arr1, $arr2 and $arr3. We then merge them into a new array $arr4 using the array_merge() function.

Summary

In PHP, adding an element to an array is a common operation. You can add elements to a PHP array using methods such as the array subscript operator [], array_push() function, key name assignment value, operator, and array_merge() function. According to different needs, choosing different methods to add elements can make programming more convenient and efficient.

The above is the detailed content of Add a pair of values ​​to the php array. For more information, please follow other related articles on the PHP Chinese website!