Remove excess commas from string PHP

I've filtered some keywords from a string, to remove invalid ones but now I have a lot of extra commas. How do I remove them so I go from this:

,,,,,apples,,,,,,oranges,pears,,kiwis,,

To this

apples,oranges,pears,kiwis

This question is unique because it also deals with commas at the start and end.

$string = preg_replace("/,+/", ",", $string);

basically, you use a regex looking for any bunch of commas and replace those with a single comma. it's really a very basic regular expression. you should learn about those!

https://regex101.com/ will help with that very much.

Oh, forgot: to remove commas in front or after, use

$string = trim($string, ",");