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.
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