PHP gets an instance of a specified column in an array

The following editor will share with you an example of PHP obtaining a specified column in an array. It has a good reference value and I hope it will be helpful to everyone. Let’s follow the editor and take a look.

For a multi-dimensional array (taking a two-dimensional array as an example), it is often necessary to obtain one of the columns. For example, there are several pieces of user data, which is a two-dimensional array. Now we need There are many ways to get the names of these users:

$arr = array( array( 'id'=>'101', 'name'=>'qu', 'age'=>28 ), array( 'id'=>'102', 'name'=>'you', 'age'=>24 ), array( 'id'=>'103', 'name'=>'zheng', 'age'=>22 ), array( 'id'=>'104', 'name'=>'zhu', 'age'=>23 ) );

Method 1: Use the PHP built-in function array_column( )Achieve

array array_column ( array $input , mixed $column_key [, mixed $index_key ] )

Execution statement:

$result = array_column($arr,'name')； print_r($result);

The results are as follows:

Array ( [0] => qu [1] => you [2] => zheng [3] => zhu )

If the optional parameter index_key is specified, then the value of this column in the input array Will serve as the key to the corresponding value in the returned array.

$result = array_column($arr,'name','id'); print_r($result);

The results are as follows:

Array ( [101] => qu [102] => you [103] => zheng [104] => zhu )

Method 2: Use PHP built-in function array_map() to implement

array array_map ( callable $callback , array $arr1 [, array $... ] )

array_map() returns an array that contains All units in arr1 are units after callback has been applied. The first parameter is a callback function, and the return value is an array. Each element of the array is processed by the callback function (callback).

First declare a processing function:

function get_val($arr){ return $arr['name']; }

Then act on the array_map() function:

$result = array_map('get_val',$arr); print_r($result);

The execution results are as follows:

Array ( [0] => qu [1] => you [2] => zheng [3] => zhu )

This The first parameter of array_map() is a callback function, and it is a well-known function defined in advance. Here we can also use anonymous functions like js:

$result = array_map(function($v){ return $v['name']; },$arr);

The execution results are the same.

The above example of PHP obtaining a specified column in an array is all the content shared by the editor. I hope it can give you a reference, and I hope you will support the PHP Chinese website.

Articles you may be interested in:

Usage analysis of PHP array access interface ArrayAccess

PHP iterator interface Iterator usage analysis

PHP aggregate iterator interface IteratorAggregate usage analysis

The above is the detailed content of PHP gets an instance of a specified column in an array. For more information, please follow other related articles on the PHP Chinese website!