PHP Gets an example of a column specified in the array to explain

The following small series for you to share a PHP to get an array of the specified list of instances, has a good reference value, I hope to be helpful. Let's take a look at it with a little knitting.

For a multidimensional array (in the case of a two-dimensional array), it is often necessary to obtain a column, such as a few user data, is a two-dimensional array, now need to obtain the names of these users, there are many ways to implement:

$arr = array (' id ' = ' = ' 101 ', ' name ' = = ' qu ', ' age ' =>28), array (' id ' = ' 102 ', ' name ' = ' " Array (' id ' = ' = ' 103 ', ' name ' = ' = ' zheng ', ' age ' =>22), array (' id ' = ' 104 ', ' name ' = = ' Zhu ', ' age ' =>23)) ;

Method One: Use PHP built-in function array_column () to implement

Array Array_column (array $input, mixed $column _key [, Mixed $index _key])

Execute statement:

$result = Array_column ($arr, ' name '); Print_r ($result);

The results are as follows:

Array (  [0] = Qu  [1] = you  [2] = Zheng  [3] = = Zhu)

If an optional parameter index_key is specified, the value of this column in the input array will be the key that returns the corresponding value in the array.

$result = Array_column ($arr, ' name ', ' id '); Print_r ($result);

The results are as follows:

Array (  [101] = Qu  [102] = [  103] = Zheng  [104] = Zhu)

Method two: Using PHP built-in function array_map () implementation

Array Array_map (callable $callback, array $arr 1 [, Array $ ...]

Array_map () returns an array that contains all the cells in the ARR1 after the callback action. The first parameter is a callback function, and the return value is an array in which each element of the array (ARR1) is processed by a callback function (callback).

Declare a handler function first:

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

Then act on the Array_map () function:

$result = Array_map (' Get_val ', $arr); Print_r ($result);

The results of the implementation are as follows:

Array (  [0] = Qu  [1] = you  [2] = Zheng  [3] = = Zhu)

Here the first parameter of Array_map () is a callback function, and is a well-defined known function, here we can also use the anonymous function like JS:

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

The result of the execution is the same.

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