Can't set key value array to an array using foreach loop

Question

<?php
$array = array(
    array('key' => 'value'),
    array('key' => 'value'),
    array('key' => 'value')
);

foreach($array as $a) {
    $a['anotherkey'] = 'anothervalue';
}
?>

I am trying to add another key value ('anotherkey' => 'anothervalue') into each array inside $array. However the above code does not work and I can't seem to figure out why, is it because the $a['anotherkey'] could not add the value to the real array ? And what is the proper way to adding the keyvalue pair into each of the array inside $array using foreach loop ? Thank you.

Kinshuk Lahiri · Accepted Answer · 2017-05-20 03:28:50Z

2

Try this:

 $array = array(
   array('key' => 'value'),
   array('key' => 'value'),
   array('key' => 'value')
);

foreach($array as &$a) {
  $a['anotherkey'] = 'anothervalue';
}

print_r($array);

Pass By Reference used above. Read here : http://php.net/manual/en/language.references.pass.php

Hope this helps.

edited May 20, 2017 at 3:28

answered May 20, 2017 at 3:23

Kinshuk Lahiri

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6 Comments

Charas Over a year ago

Wow, it works, thank you so much. I wonder why though, could you care to explain a little bit on the '&' sign and why without it the loop doesn't work ? Thx :)

Kinshuk Lahiri Over a year ago

@Charas I have added the link above for you. Please go through it. :)

Charas Over a year ago

Great ! Thanks a lot.

Kinshuk Lahiri Over a year ago

@Charas Glad to help :)

Jeffrey Van Alstine Over a year ago

There's a bug in PHP5/7 make sure you unset($a) after the foreach loop or you can get some funny bugs.

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