array_column() is an inbuilt PHP function which can be used to get the values from a single column from the given multi-dimensional array or an array of objects.
Syntax
array array_column ( array $input , mixed $column_key [, mixed $index_key = NULL ] )Support: (PHP 5>=5.5.0, PHP 7)
Parameters for array_column()
$input
- The first parameter is mandatory.
- It should be a multi-dimensional array or an array of objects from which to fetch/retrieve a column of values from.
- With an array of objects, public properties can be directly fetched.
- Whereas for protected or private properties, the class must implement both the
__get()and__isset()methods.
$column_key
- The second parameter is also mandatory.
- It should be the column key for which values are to be fetched from a multi-dimensional array or an array of objects.
- This value may be an integer key of the column you wish to retrieve, or it may be a string key name for an associative array or property name for an array of objects.
$index_key
- The third parameter is an optional one.
- The column whose values are used as the index/keys for the returned/resulting array.
- This value may be the integer key of the column, or it may be the string key name.
Return Type
The return type of array_column() function is an another resultant array.
array_column() function returns a 1-D array which contains values from a single column of the given array, which is identified by a column_key.
Optionally, an index_key may also be provided to index the values in the resulted array by the values from the index_key column of the given array.
Example #1 Get the column of countries from a record-set
$records = [
[
'id' => 12,
'country' => 'India',
'capital' => 'New Delhi',
],
'Spain' => [
'id' => 24,
'country' => 'Spain',
'capital' => 'Madrid',
],
[
'id' => 91,
'country' => 'Israel',
'capital' => 'Jerusalem',
],
'Netherlands' => [
'id' => 121,
'country' => 'Netherlands',
'capital' => 'Amsterdam',
]
];
$countries = array_column($records, 'country');
echo "<pre>";
print_r($countries);
echo "</pre>";The above example will output
Array
(
[0] => India
[1] => Spain
[2] => Israel
[3] => Netherlands
)Example #2 Get the column of capitals from a record-set, indexed by their respective “country” column
echo "<pre>";
$capitalsWithCountries = array_column($records, 'capital', 'country');
print_r($$capitalsWithCountries);
echo "</pre>";The above example will output
Array
(
[India] => New Delhi
[Spain] => Madrid
[Israel] => Jerusalem
[Netherlands] => Amsterdam
)Conclusion
A good programming technique is trying to avoid the use of loops, nested loops & callback functions. The array_column() helps to reduce the code complexity and increases the code readability.
For more refer to the official documentation for same in manual.
Hope you find this helpful.
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