Replacing multiple `-` with one `-` without regexp - php

Question

I've seen so many misuses of RegExp, I don't really like it :)
I have string (as a result of two str_replaces) that might look something like this:
.?This iš my ".stRiNg."!
|
V
--this-is-my---string---
Is there any way better than
$string = trim(preg_replace('/[-]+/u','-', $string),'-');
to get:
this-is-my-string
?

Answer 1

preg_replace() wins
<?php
function benchmark($callback){
echo sprintf('%-30s: ', $callback);
$t = microtime(true);
foreach(range(1, 10000) as $n){
call_user_func($callback);
}
echo (microtime(true)-$t)."\n";
}
function implode_explode_filter(){
implode('-', array_filter(explode('-', '--this-is-my---string---')));
}
function preg_replace_trim(){
preg_replace('/-+/', '-', trim('--this-is-my---string---', '-'));
}
function brant(){
$parts = explode("-",'--this-is-my---string---');
for($i=0;$i<count($parts);$i++) {
if (strlen($parts[$i]) < 1) {
unset($parts[$i]);
}
}
reset($parts);
$string = implode("-",$parts);
}
function murze_bisko(){
$string = "--this-is-my---string---";
while (strpos($string, "--") !== false) {
$string = str_replace("--", "-", $string);
}
$string = trim($string, '-'); # both of their answers were broken until I added this line
}
benchmark('implode_explode_filter');
benchmark('preg_replace_trim');
benchmark('brant');
benchmark('murze_bisko');
# Output
# implode_explode_filter : 0.062376976013184
# preg_replace_trim : 0.038193941116333
# brant : 0.11686086654663
# murze_bisko : 0.058025121688843
?>

Answer 2

I don't understand why you are looking for a 'better' way. Your way uses a simple regex in a place where it's perfectly appropriate to do so. What could be better than that?

Answer 3

print implode('-', array_filter( explode( '-', $string) ) );
Easy. :)

Answer 4

A better way? Probably not. Another way? Yes (essentially one-line version of Brant's answer):
implode('-', array_filter(explode('-', $string), function($s) { return strlen($s); }));
Note that you can't just use the naked array_filter reliably, because !!"0" == false in PHP.

Answer 5

$parts = explode("-",'--this-is-my---string---');
for($i=0;$i<count($parts);$i++) {
if (strlen($parts[$i]) < 1) {
unset($parts[$i]);
}
}
reset($parts);
$string = implode("-",$parts);

Answer 6

So you want to go from
--this-is-my---string---
to
this-is-my-string?
The best way would be a reg exp, but if you want a simple solution in php you can use
$string = "--this-is-my---string---";
while (! strpos($string, "--") === false) {
$string = str_replace("--", "-", $string);
}
After the loop $string will contain the result.

Answer 7

Just for the sake of the competition:
$string = str_replace('--','-', str_replace('--','-', '--this-is-my---string---'));
This is the fastest way to do it. It first replaces double -- with single and then cleans the rest again, so only single - remain.