How to add array elements in php

In PHP, array is a very common and widely used data type. There are many situations where we need to add elements to an array. This article will introduce different methods and techniques for adding array elements in PHP.

1. Using array subscripts

To add a new element to an array, you can use the array subscript. The syntax for using array subscripts in PHP is very simple. You only need to add square brackets after the array variable, and then write the subscript of the new element in the square brackets. For example:

$fruits = array('apple', 'banana', 'orange');
$fruits[3] = 'watermelon'

In the above example, we defined an array named $fruits and added an array named 'watermelon' to it new element. Since this element is the fourth element in the array, we use the subscript 3 to specify its position.

It should be noted that if you use an existing subscript to add a new element, it will overwrite the original value. For example:

$fruits[2] = 'grape'

In this example, we replace the third element in the fruits array ('orange' in the above example) with ' grape'.

2. Using the array_push function

PHP also provides a built-in function array_push, which can add one or more elements to the end of the array. The syntax for using the array_push function is very simple. You only need to pass the elements to be added as function parameters. For example:

$fruits = array('apple', 'banana', 'orange');
array_push($fruits, 'watermelon', 'grape');

In the above example, we have added two new elements to the array named $fruits, namely 'watermelon' and 'grape'.

It should be noted that the array_push function always adds elements to the end of the array, even if it already exists. This means that if you add an element to the array that already exists, it will still be added to the end of the array and increase the array length by one.

3. Using the "=" Operator

There is also a neat way to add multiple elements to an array, which is to use the "=" operator in PHP. What this operator does is add all elements of the right operand to the array of the left operand. For example:

$fruits = array('apple', 'banana');
$fruits += array('orange', 'watermelon');

In the above example, we compare an array containing two elements 'apple' and 'banana' with another array containing two elements The arrays of 'orange' and 'watermelon' are added, and the result is an array containing four elements, whose values ​​are 'apple', 'banana', 'orange' and 'watermelon'.

It should be noted that if the same key (that is, the same subscript) exists in the added arrays, the "=" operator will not replace the existing elements. Instead, it ignores these elements.

4. Using the "[]" operator

PHP's "[]" operator can not only be used to get elements in an array, but can also be used to add elements. If you provide a new key name using the "[]" operator, it will add a new element to the array. For example:

$fruits = array('apple', 'banana');
$fruits[] = 'orange';

In the above example, we added a new element 'orange' to the array named $fruits. Since we did not specify the subscript of the new element, PHP will automatically use the maximum subscript of the current array to add the new element to the end of the array.

It should be noted that if you do not use the "[]" operator when adding a new element to the array, but use the dot (.) for string concatenation, it will not become a new element of the array. element, but becomes part of the string.

The above are the methods of adding array elements in PHP. Each method has its own advantages and applicable scenarios, and should be selected and used according to actual needs.

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