How to store associative array in php

Associative array is a very important data type in PHP and one of the data types that is used relatively frequently. Associative arrays can store a series of key-value pairs in an array, where the keys and values ​​can be of any data type, including numbers, strings, arrays, etc. In PHP, there are many ways to store associative arrays. This article will introduce one of the common methods: storing them one by one.

1. Create an associative array

In PHP, creating an associative array is very simple, just use the array() or [] operator. Among them, array() is a function, and the [] operator is an array literal. Key-value pairs in an associative array can be separated by a colon (:) or an equal sign (=), as shown below:

// 使用 array() 函数创建How to store associative array in php
$arr1 = array("name" => "张三", "age" => 18, "gender" => "男");

// 使用数组字面量 [] 创建How to store associative array in php
$arr2 = ["name": "李四", "age": 20, "gender": "女"];

In the above code, $arr1 and $arr2 are both associative arrays, and they are represented by It consists of three key-value pairs. Each key-value pair consists of a key and a value. The keys of $arr1 are "name", "age" and "gender", and the corresponding values ​​are "Zhang San", 18 and "male", while the keys of $arr2 are "name", "age" and "gender" respectively, and the corresponding values ​​are "John Doe", 20 and "female" respectively.

2. Store associative arrays one by one

In PHP, you can add key-value pairs to associative arrays by storing them one by one. This method is suitable for situations where associative arrays need to be dynamically created or there are many key-value pairs. Let’s take a look at the specific process.

1. Create an empty associative array

First create an empty associative array $employees, and then add employee information one by one, where each employee information includes name, gender ( Four attributes: gender), age (age) and position (position). The code is as follows:

$employees = [];

2. Add employee information

Next we add employee information to the associative array $employees one by one. As shown below:

$employees['person1']['name'] = '张三';
$employees['person1']['gender'] = '男';
$employees['person1']['age'] = 28;
$employees['person1']['position'] = '项目经理';

$employees['person2']['name'] = '李四';
$employees['person2']['gender'] = '女';
$employees['person2']['age'] = 25;
$employees['person2']['position'] = 'UI设计师';

$employees['person3']['name'] = '王五';
$employees['person3']['gender'] = '男';
$employees['person3']['age'] = 32;
$employees['person3']['position'] = '技术总监';

In the above code, we first assign a number to each employee, such as person1, person2 and person3, as a key. Then, for each employee, we use the form $employees['person1'] to specify the key to which the employee's key-value pair belongs, and add the name, gender, age and position attributes to the employee by assigning values ​​one by one, such as $employees'person1' = 'Zhang San'.

3. Output employee information

Finally, we can output the employee information stored in the $employees associative array through a loop. The code is as follows:

foreach ($employees as $personKey => $personValue) {
    echo "<strong>员工编号：$personKey</strong><br>";
    foreach ($personValue as $detailKey => $detailValue) {
        echo "$detailKey：$detailValue<br>";
    }
    echo '<br>';
}

The output result is as shown in the figure below:

As can be seen from the above code and results, we use the method of storing one by one to associate Adding key-value pairs to the array finally outputs the data stored in the associative array in a more intuitive way.

Summary

Associative array is a very powerful data type in PHP. It can store multiple key-value pairs in an array. Each key-value pair can be composed of a key and a Composed of values, which can be of any data type. In PHP, you can create and operate associative arrays through a variety of methods. The one-by-one storage method is suitable for situations where you need to dynamically create an associative array, or when there are many key-value pairs. No matter which method is used, mastering the use of associative arrays is an essential basic skill in PHP development.

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