How to use php associative array

PHP is a very powerful programming language that supports many data types, one of which is associative arrays. Unlike ordinary arrays, associative arrays are one-to-one key-value pairs, and any type of value can be used as the key name of the array, not just numbers. In PHP development, associative arrays are a very commonly used data type. This article will introduce the basic usage of associative arrays.

1. Create an associative array

To create an associative array, just use the array() function. The following is a simple example:

$info = array(
    'name' => '张三',
    'age' => 24,
    'sex' => '男'
);

The above code creates an associative array named $info, which contains three key-value pairs, namely 'name', 'age' and 'sex'. The value of 'name' is the string 'Zhang San', the value of 'age' is the number 24, and the value of 'sex' is the string 'male'.

2. Accessing associative arrays

The method of accessing associative arrays is similar to that of ordinary arrays, you only need to use the key name. The following is a simple example:

echo $info['name']; // 输出：张三
echo $info['age']; // 输出：24
echo $info['sex']; // 输出：男

As you can see, when using an associative array to access elements, you only need to use the key name. The advantage of this is that it can make the code clearer and easier to read.

3. Traversing associative arrays

The method of traversing associative arrays is similar to that of ordinary arrays, and can be implemented using a foreach loop. The following is a simple example:

foreach($info as $key => $value) {
    echo "键名：{$key}，键值：{$value}<br/>";
}

The above code uses a foreach loop to traverse the $info array, where $key represents the key name and $value represents the key value. In the loop body, the contents of each key name and key value are output.

4. Modify the associative array

The method of modifying the associative array is also very simple, just use the key name. The following is a simple example:

$info['name'] = '李四';
$info['age'] = 25;
$info['sex'] = '女';

The above code modifies the values ​​of $name, $age and $sex respectively, changing them to '李思', 25 and 'Female' respectively.

5. Delete associative array elements

The method of deleting associative array elements is also very simple, just use the unset() function. The following is a simple example:

unset($info['sex']);

The above code deletes the 'sex' key-value pair in the $info array.

In short, associative arrays are one of the data types often used in PHP programming. Proficiency in their basic usage is very important for developing PHP programs. This article introduces the basic operation methods of creating, accessing, traversing, modifying and deleting associative arrays. It is a very useful reference for beginners.

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