How to combine Regex with removing space and # character - php

Question

I have this array, that I need to remove white spaces and # hashtag character:
array (size=7)
0 => string 'darwin' (length=6)
1 => string ' #nature' (length=8)
2 => string ' explore' (length=8)
3 => string ' galapagos' (length=10)
4 => string 'karma' (length=5)
foreach ($feedSinglePosts["hashtags_list"] as $key=>&$item) {
$item = preg_replace('/(\s|^)/', '', $item);
$item = preg_replace('/\#+/', '', $item);
}
The Regex above works well but I want to make it one line if possible.
When I do: /(\s|^)\#+/ it outputs this:
array (size=7)
0 => string 'darwin' (length=6)
1 => string 'nature' (length=6)
2 => string ' explore' (length=8)
3 => string ' galapagos' (length=10)
4 => string 'karma' (length=5)
How to make the regex on liner that removes white spaces and3 hashtag.

Answer 1

It appears that the characters will be at the beginning or end. If so then no need for loops or regex:
array_walk($feedSinglePosts["hashtags_list"], function(&$v) { $v = trim($v, "\n\r #"); });
If you need to remove them anywhere:
$feedSinglePosts["hashtags_list"] = str_replace(["\n","\r"," ","#"], "", $feedSinglePosts["hashtags_list"]);

Answer 2

A non-regex way with array_walk() and trim(),
<?php
$array = ['darwin' ,' #nature',' explore', ' galapagos','karma'];
function remove_hash_space(&$value,$key){
$value = trim($value,'# ');
}
array_walk($array, 'remove_hash_space');
print_r($array);
?>
DEMO: https://3v4l.org/nOadH
OR with single line array_map(),
$array = array_map(function($e){return trim($e,'# ');},$array);
DEMO: https://3v4l.org/OaS1F

Answer 3

You may use
$arr = ['darwin',' #nature',' explore',' galapagos','karma'];
print_r( preg_replace('~^[\s#]+~', '', $arr) );
// => Array ( [0] => darwin [1] => nature [2] => explore [3] => galapagos [4] => karma )
See the regex demo
The ^[\s#]+ pattern matches 1 or more occurrences (+) of whitespace or # characters ([\s#]) at the start of the string (^).
If your strings may contain some wierd Unicode whitespace, consider adding the u modifier: ~^[\s#]+~u.
If you only need to handle horizontal whitespace, replace \s with \h.