How to Extract a Single Column from a Multi-Dimensional Array in PHP?

Return Single Column from a Multi-Dimensional Array

A common requirement in PHP is to extract a single column from a multi-dimensional array. For instance, consider an array with the following structure:

Array
(
    [0] => Array
        (
            [blogTags_id] => 1
            [tag_name] => google
            [inserted_on] => 2013-05-22 09:51:34
            [inserted_by] => 2
        )

    [1] => Array
        (
            [blogTags_id] => 2
            [tag_name] => technology
            [inserted_on] => 2013-05-22 09:51:34
            [inserted_by] => 2
        )
)

Implode Function

You can use the implode() function to concatenate the values of a specific column, such as the tag_name key. To do this, pass an array of the extracted values to implode():

$tagNames = array();

foreach ($array as $row) {
    $tagNames[] = $row['tag_name'];
}

$commaSeparatedTags = implode(', ', $tagNames);

This code will produce the desired output:

google, technology

Alternate Solution: array_column()

PHP 5.5 introduced the array_column() function, which provides a simpler way to extract a single column from an array:

$tagNames = array_column($array, 'tag_name');

$commaSeparatedTags = implode(', ', $tagNames);

Both methods offer solutions to the problem of extracting a single column from a multi-dimensional array. Choose the approach that best suits your PHP version and requirements.

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