How to get a specified column in an array in PHP (case)

This article mainly introduces how to obtain a specified column in an array in PHP. Interested friends can refer to it. I hope it will be helpful to everyone.

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

$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 PHP built-in function array_column() to implement

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

Execute the statement:

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

The result is as follows:

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

If the optional parameter index_key is specified, the value of this column in the input array will be used 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 the items in arr1 The unit after the callback has been applied to the unit. 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 result is as follows:

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

The first parameter of array_map() here 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.

Related recommendations:

PHP gets the specified value position in the array

PHP method to get a specified column in the array

How does js get an array and process a php array

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