How to remove an array from a two-dimensional array in php

PHP is a popular programming language often used in web development. In PHP development, dealing with arrays is very common. An array is an ordered data type that can store multiple values. However, sometimes we need to operate on two-dimensional arrays, such as removing two-dimensional arrays. In this article, we will discuss how to remove an array from a 2D array in PHP.

1. What is a two-dimensional array

In PHP, an array can contain other arrays. Such an array is a two-dimensional array. We can think of a two-dimensional array as a table, where each element is a cell. Each cell in turn contains an array. For example, the following example:

$students = array(
    array('name' => '张三', 'score' => 90),
    array('name' => '李四', 'score' => 80),
    array('name' => '王五', 'score' => 70)
);

The above code defines a student array, in which each student consists of an array containing "name" and "grade".

2. Remove an array from a two-dimensional array

Sometimes, we need to remove one dimension of a two-dimensional array, that is, take out the array from the two-dimensional array. For example, we want to extract all the names in the student array above. You can use a foreach loop to traverse the two-dimensional array. The code is as follows:

$names = array();
foreach ($students as $student) {
    $names[] = $student['name'];
}

The above code will save the name of each student in the student array into a new array $names. In the foreach loop, the element $student obtained each time it is traversed is a one-dimensional array containing names and grades.

Sometimes, we need to remove the value corresponding to a certain key in the two-dimensional array. For example, we want to remove the grades of all students in the student array above. You can use the array_map function to process a two-dimensional array. The code is as follows:

$names = array_map(function($student) {
    unset($student['score']);
    return $student;
}, $students);

The above code will remove the grades of each student in the student array and return a new array. In the array_map function, we define an anonymous function that accepts a student array, uses the unset function to remove the value corresponding to the "grade" key, and finally returns the processed student array.

3. Summary

In PHP, processing arrays is very common. Sometimes, we need to operate on two-dimensional arrays, such as removing two-dimensional arrays. This article introduces how to use the foreach loop and array_map function to process two-dimensional arrays, and gives sample code. I hope this article can help you deal with two-dimensional arrays in PHP development.

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