How to convert a two-dimensional array to an one-dimensional array by php

This article mainly explains how php converts a two-dimensional array into an one-dimensional array. Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "php how to convert a two-dimensional array into an one-dimensional array".

Php two-dimensional array to one-dimensional array method: 1, with array_column () function; 2, with array_walk () function; 3, with array_map () function; 4, with array_reduce () function; 5, with array_walk_recursive () function.

Operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

Summary of two-dimensional array to one-dimensional array

For example, convert the following two-digit array to an one-dimensional array

$records = [['id' = > 2135,' first_name' = > 'John',' last_name' = > 'Doe',], [' id' = > 3245, 'first_name' = >' Sally', 'last_name' = >' Smith',], ['id' = > 5342,' first_name' = > 'Jane'] 'last_name' = >' Jones',], ['id' = > 5623,' first_name' = > 'Peter',' last_name' = > 'Doe',]]

1.array_column ()

Array_column () is a PHP built-in function, and the restriction is that the PHP version must be 5.5.0 or above!

Example 1:

The print result is as follows:

Example 2:

The print result is as follows:

2.array_walk ()

The array_walk () function uses a user-defined function to callback each element in the array to achieve the current function:

$first_names= []; array_walk ($records, function ($value, $key) use (& $first_names) {$first_names [] = $value ['first_name'];}); var_dump ($first_names)

The print result is as follows:

3.array_map ()

The array_map () function acts similarly to array_walk (), applying the callback function to the cells of a given array.

$first_names= []; array_map (function ($value) use (& $first_names) {$first_names [] = $value ['first_name'];}, $records); var_dump ($first_names)

The print result is as follows:

4.array_reduce ()

Array_reduce-use the callback function to iteratively simplify the array to a single value.

$first_names = array_reduce ($records,function ($result, $value) {array_push ($result, $value ['first_name']); return $result;}, []); var_dump ($first_names)

Print the results:

5. Array_walk_recursive ()

Array_walk_recursive-applies the user function recursively to each member of the array. This function can convert an array of any dimension into an one-dimensional array.

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