How to add content to an array in php

In PHP development, array is a very commonly used data type. Adding content to an array is also a basic operation. This article will explain how to add content to an array in PHP.

Whether it is a numerically indexed array or an associative array, PHP provides a simple way to add content to the array. The two types of arrays will be explained below.

1. Add content to a numeric index array

Numeric index array is the most basic array type, and array elements are accessed through numeric subscripts. There are two ways to add content to a numerically indexed array: using the array_push function and directly using the [] operator.

1.1 Using the array_push function

array_push The function adds one or more elements to the end of an array. The syntax is as follows:

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

Among them, array represents the array to which elements are to be added, and value1, value2, etc. represent the elements to be added.

For example:

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

After execution, the value of the $fruits array will become ["apple", "banana", "orange"].

If you want to add multiple elements at the same time, you can list each element in sequence in the function, for example:

$fruits = array("apple", "banana");
array_push($fruits, "orange", "peach", "watermelon");

After execution, the value of the $fruits array will change Into["apple", "banana", "orange", "peach", "watermelon"].

1.2 Direct use of the [] operator

Direct use of the [] operator can also add elements to a numeric index array. The syntax is as follows:

$array[] = value;

Among them, $array represents the array to which elements are to be added, and value represents the elements to be added.

For example:

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

After execution, the value of the $fruits array will become ["apple", "banana", "orange"].

If you want to add multiple elements at the same time, you can use multiple [] operators, for example:

$fruits = array("apple", "banana");
$fruits[] = "orange";
$fruits[] = "peach";
$fruits[] = "watermelon";

After execution, $fruits array The value will become ["apple", "banana", "orange", "peach", "watermelon"].

2. Add content to an associative array

Associative array is an array type that uses strings as key names, and is also very commonly used in PHP. There are also two ways to add content to an associative array: using the $array['key'] = value syntax and using the array_merge function.

2.1 Use$array['key'] = value Syntax

Use$array['key'] = value Syntax can be associated Add a key-value pair to the array. Among them, $array represents the array to which elements are to be added, key represents the key name to be added, and value represents the value to be added.

For example:

$person = array("name" => "Tom", "age" => 20);
$person["gender"] = "male";

After execution, the value of the $person array will become ["name" => "Tom", "age" = > 20, "gender" => "male"].

2.2 Use the array_merge function

array_merge The function can merge multiple arrays into one array, or add elements to an array. The syntax is as follows:

array_merge(array1, array2, ...)

Among them, array1, array2, etc. represent the arrays to be merged.

For example:

$person = array("name" => "Tom", "age" => 20);
$person = array_merge($person, array("gender" => "male", "married" => false));

After execution, the value of the $person array will become ["name" => "Tom", "age" = > 20, "gender" => "male", "married" => false].

Note: When using the array_merge function to add elements to an array, if the key names are the same, the value of the subsequent array will overwrite the value of the previous array. If you want to retain duplicate key names, you can use the operator, for example:

$person = array("name" => "Tom", "age" => 20);
$person += array("gender" => "male", "married" => false, "age" => 25);

After execution, the value of the $person array will become [" name" => "Tom", "age" => 20, "gender" => "male", "married" => false], you can see that ## in the following array #age Key names are ignored.

Summary

In PHP, adding content to an array is very simple. Whether it is a numerically indexed array or an associative array, there are many ways to do it. Developers can choose different ways to add content based on their needs.

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