php modify nested array

Nested array is a very common data type in PHP programming. It can store data of different types and depths. In practical applications, we often need to modify nested arrays. Below we will introduce how to modify nested arrays in PHP through some cases.

1. Modify the value in the array

We can directly modify a value in the nested array through the array subscript. For example:

$data = array(
    'name' => 'Tom',
    'age' => 18,
    'address' => array(
        'province' => 'Guangdong',
        'city' => 'Shenzhen',
        'district' => 'Futian'
    )
);

$data['age'] = 19; // 直接修改 $data 数组中的 'age' 元素的值
$data['address']['district'] = 'Nanshan'; // 修改 $data 数组中 'address' 元素中的 'district' 元素的值

2. Add a new element to the nested array

If you want to add a new element to the nested array, you can add an element directly after the array , for example:

$data = array(
    'name' => 'Tom',
    'age' => 18,
    'address' => array(
        'province' => 'Guangdong',
        'city' => 'Shenzhen'
    )
);

$data['gender'] = 'male'; // 添加一个新元素
$data['address']['district'] = 'Futian'; // 添加 $data 数组中 'address' 元素中的 'district' 元素

Note that if the element you want to add already exists, the original value will be overwritten. If you want to keep the original value, you can use the array_push() function to insert the element at the end of the array.

3. Delete elements in nested arrays

With the help of PHP's unset() function, you can easily delete elements in nested arrays . For example:

$data = array(
    'name' => 'Tom',
    'age' => 18,
    'address' => array(
        'province' => 'Guangdong',
        'city' => 'Shenzhen',
        'district' => 'Futian'
    )
);

unset($data['age']); // 删除 $data 数组中的 'age' 元素
unset($data['address']['district']); // 删除 $data 数组中 'address' 元素中的 'district' 元素

Note that when using the unset() function to delete an array element, the subscript of the element will be removed. When an element is deleted, the keys of the array are rearranged, so the deleted element does not retain its original position. Therefore, if you need to delete an element in a nested array and maintain the original order of elements, you need to use the array_splice() function.

4. Modify the key name of the nested array

When modifying the key name of the nested array, you usually need to use PHP's unset() The function deletes the original key and adds the element using the new key name. For example:

$data = array(
    'name' => 'Tom',
    'age' => 18,
    'address' => array(
        'province' => 'Guangdong',
        'city' => 'Shenzhen',
        'district' => 'Futian'
    )
);

unset($data['age']); // 删除 $data 数组中的 'age' 元素
$data['new_age'] = 19; // 添加一个新元素

It should be noted that if the original key name is repeated in the array, all elements with the same name will be deleted when deleting the element.

The above is the modification method of nested arrays in PHP, which needs to be used flexibly according to the actual application scenario. In practical applications, nested arrays are a frequently used data type. Modifying the data in nested arrays will make it easier for developers to operate and manage data.

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