Change array keys to lowercase

Question

I'm looking for a nifty php solution to replace a standard forloop. i dont care at all about the inner workings of my normalize method.

Here is my code:

$pairs=[];
foreach($items as $key => $val){
    $key = $this->normalizeKey($key);
    $pairs[$key] = $val;
}

private function normalizeKey($key)
{
    // lowercase string
    $key = strtolower($key);

    // return normalized key
    return $key;
}

I'd like to learn the PHP language a bit better. I thought array_walk would be nice to use, but that operates on the values and not the keys.

I am looking for a PHP array method that can perform this code instead of a foreach loop.

Possible duplicate of how to change array keys from uppercase to lowercase? — bwoebi
– bwoebi, Commented Aug 20, 2016 at 22:39

Sherif · Accepted Answer · 2016-08-20 21:41:38Z

17

You want array_change_key_case

$pairs = array_change_key_case($items);

answered Aug 20, 2016 at 21:41

Sherif

12k3 gold badges36 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

AbraCadaver · Accepted Answer · 2016-08-20 22:39:07Z

1

Just for fun, though it requires three functions. You can replace strtolower() with whatever since this can already be done with array_change_key_case():

$pairs = array_combine(array_map('strtolower', array_keys($items)), $items);

Get the keys from $items
Map the array of keys to strtolower()
Combine the new keys with $items values

You can also use an anonymous function as the callback if you need something more complex. This will append -something to each key:

$pairs = array_combine(array_map(function ($v) {
                                     return $v . '-something';
                                 },
                       array_keys($items)), $items);

edited Aug 20, 2016 at 22:39

answered Aug 20, 2016 at 21:55

AbraCadaver

79.2k7 gold badges75 silver badges91 bronze badges

Comments

Peter Chaula · Accepted Answer · 2022-02-19 18:42:37Z

-2

You can normalise the keys and store them and their corresponding values in a temporary array and assign it to your original $pairs array.

Like so:

$normalised = [];

foreach($pairs as $key => $value) {
    $normalised[$this->normalizeKey($key)] = $value;
};

$pairs = $normalised;

Edit 2022: Or better yet, use @Sherif's answer as it uses a standand library function

edited Feb 19, 2022 at 18:42

answered Aug 20, 2016 at 21:41

Peter Chaula

3,7812 gold badges36 silver badges37 bronze badges

4 Comments

AbraCadaver Over a year ago

The function may be defined as (&$value, $key) but not (&$value, &$key). Even though PHP does not complain/warn, it does not modify the key.

Peter Chaula Over a year ago

@AbraCadaver I just noticed. It doesn't even throw an error. Thanks! I'll notify the OP

bwoebi Over a year ago

@Sherif It's not undefined behavior, it just does not work the way intended.

Peter Chaula Over a year ago

Modified answer and it works with any implementation of normalizeKey method

Collectives™ on Stack Overflow

Change array keys to lowercase

3 Answers 3

Comments

Comments

4 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related