How to set up associative array in php

In the PHP language, an associative array is a special type of array, which is characterized by using strings as array subscripts to form a "key-value pair" form. Associative arrays are widely used in PHP development and are very convenient. Let’s take a closer look at how to set up associative arrays in PHP.

1. Creating an associative array

There are many ways to create an associative array. Two of the more common methods are listed below.

Method 1: Use the array function

You can use the array function to create an associative array. The syntax is as follows:

$array = array(key1 => value1, key2 => value2, ...);

where key1 and key2 represent the key names of the array, and value1 and value2 are the key values ​​corresponding to the key names.

Sample code:

$userInfo = array('name' => 'Tom', 'age' => 20, 'gender' => 'male');

Method 2: Direct assignment

Add elements to the associative array directly through assignment. The syntax is as follows:

$array[key] = value;

Sample code:

$userInfo['name'] = 'Tom';
$userInfo['age'] = 20;
$userInfo['gender'] = 'male';

2. Accessing associative arrays

The method of accessing associative arrays is the same as that of ordinary arrays, through array subscripts Just access the array elements. The syntax is as follows:

$array[key];

Sample code:

echo $userInfo['name']; //输出：Tom
echo $userInfo['age']; //输出：20
echo $userInfo['gender']; //输出：male

3. Traverse associative arrays

The way to traverse associative arrays is the same as that of ordinary arrays. The most common ones are foreach loops and while loop in two ways.

Method 1: Use foreach loop

Use foreach loop to traverse the associative array to traverse all elements in it. The syntax is as follows:

foreach($array as $key => $value){
    //执行操作
}

Sample code:

foreach($userInfo as $key => $value){
    echo $key . ': '. $value . '<br>';
}

//输出：
//name: Tom
//age: 20
//gender: male

Method 2: Using while loop

To use a while loop to traverse an associative array, you need to use the each function. The each function returns the index and value of the current element in the array and moves the internal pointer backward. When the array is traversed, the each function will return false. The syntax is as follows:

while(list($key, $value) = each($array)){
    //执行操作
}

Sample code:

while(list($key, $value) = each($userInfo)){
    echo $key . ': '. $value . '<br>';
}

//输出：
//name: Tom
//age: 20
//gender: male

Summary

The above is an introduction to PHP associative array settings. Associative arrays are widely used in PHP development, have very practical functions, and are suitable for various scenarios. Through the above methods, you can easily create, access and traverse associative arrays and solve problems quickly.

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