PHP array_column() Function

Syntax of PHP array_column() Function

The syntax of the array_column() function is relatively simple:

Parameter Values of PHP array_column() Function

• input: This parameter accepts an array of arrays or an array of objects. It's the source from which data will be extracted.
• column_key: The column to be extracted from each sub-array or object in the input. This can be either an integer (index of the column) or a string (column name).
• index_key: This optional parameter defines the column to be used as the index/key of the resulting array. If not provided, the resulting array will be indexed numerically.

Return Values of PHP array_column() Function

The array_column() function returns an array containing the extracted column values. The keys of the returned array can either be the numerical index of the sub-array or the values from the specified index column.

Example

Get Column of Last Names from a Record Set

Suppose we have a record set that stores user information, including first names and last names. We can easily extract the last names using array_column():

Output

Explanation In this example, we have an array called $users that stores user information, including their IDs, first names, and last names. The array_column() function is used to extract the last names from the $users array and create a new array called $lastNames containing only the last names. The print_r() function is then used to display the contents of the $lastNames array.

Get Column of Last Names from a Recordset, Indexed by the "id" Column

We might want to create an associative array with the "id" column as keys and the corresponding last names as values:

Output

Explanation In this example, we have an array called $users that stores user information, including their IDs, first names, and last names. The array_column() function is used to extract the last names from the $users array and create an associative array where the IDs serve as keys and the corresponding last names are the values. The resulting $lastNamesIndexedById array will contain the last names indexed by the user IDs. When the code is executed, the print_r() function is used to display the contents of the $lastNamesIndexedById array.

Get the Column of First Names from a Recordset

Similarly, we can extract the first names from the record:

Output

Explanation In this example, we have an array called $users that stores user information, including their IDs, first names, and last names. The array_column() function is used to extract the first names from the $users array and create a new array called $firstNames containing only the first names. The print_r() function is then used to display the contents of the $firstNames array.

Get the Column of First Names from a Recordset but Index Recordset Using "id"

Here, we can achieve the same result as above while indexing the array by the "id" column

Output

Explanation In this example, we have an array called $users that stores user information, including their IDs, first names, and last names. The array_column() function is used to extract the first names from the $users array and create an associative array called $firstNamesIndexedById. The keys of this associative array are the user IDs, and the corresponding values are the extracted first names. The print_r() function is then used to display the contents of the $firstNamesIndexedById array.

More Examples

Let's explore further scenarios where array_column() proves its versatility:

Extracting Numeric Data

If we have an array of arrays representing sales data, we can easily extract the sales figures:

Output

Explanation In this example, we have an array called $salesData that represents sales data for different months. Each element of the array contains a month and its corresponding sales figure. The array_column() function is used to extract the sales figures from the $salesData array and create a new array called $sales containing only the sales values. The print_r() function is then used to display the contents of the $sales array.

Working with Objects The function isn't limited to arrays, it also works seamlessly with arrays of objects. Consider an array of Book objects, and we want to extract their titles:

Output

Explanation In this example, we have a Book class that represents a book object with properties for the book's ID and title. The $books array is an array of Book objects, each instantiated with a unique ID and title. The array_column() function is used to extract the titles from the $books array and create a new array called $bookTitles containing only the book titles. The print_r() function is then used to display the contents of the $bookTitles array.