Member Avatar for rajeesh_rsn

Hi,

I need to replace "-" from a string . Ie

Just need a "-" between two words. ie

standard format is : Hello-world-php

If I got a string like this 'Hello--world----php'

I just need to rewrite that in to 'Hello-world-php' format .

Hope you understand this ..

Please help
Thanks
Rajeesh

  • 5 Contributors
  • 5 Replies
  • 207 Views
  • 8 Hours Discussion Span
  • Latest Post Latest Post by chrishea

Dani AI

Generated

For : the goal is to collapse every run of consecutive hyphens into a single hyphen (so Hello--world----php -> Hello-world-php). ’s regex approach is the cleanest and most concise because it replaces whole runs at once. The str_replace suggestions from and only work if you keep applying them repeatedly — str_replace does not re-scan text it has already replaced.

If you prefer to avoid regex, a single-pass PHP routine is simple and safe:

function collapse_hyphens($s) {
    $out = '';
    $len = strlen($s);
    for ($i = 0; $i < $len; $i++) {
        $ch = $s[$i];
        if ($ch === '-') {
            if ($out === '' || $out[strlen($out) - 1] !== '-') {
                $out .= '-';
            }
        } else {
            $out .= $ch;
        }
    }
    return $out;
}

Example:

$in = 'Hello--world----php';
echo collapse_hyphens($in); // Hello-world-php

Notes and gotchas: use trim($result, '-') if you also want to remove leading/trailing hyphens. For strings that may include different dash characters (en-dash, em-dash) or multibyte text, normalize those characters first or use a Unicode-aware regex. For typical ASCII input and most workloads, the regex solution mentioned by is both shorter and faster; use the loop above when you need explicit byte-level control or want to avoid regular expressions.

Recommended Answers

All 5 Replies

Member Avatar for chrishea

You can use:

$result = str_replace ("--","",$string);
Member Avatar for tomato.pgn

chrishea is telling nice solution...but you have to just manage and search in your string that how many consecutive '-' are present....and then use the method told by him...Hope it's clear...

Member Avatar for makman99 
$result = str_replace ("--","-",$string);

Should remove all
if there's 3 in a row: ---
It would find the first two - and replace with one: [-]-
leaving -- which is then replaced by -

Edited by makman99 because: n/a
Member Avatar for Insensus 
$result = str_replace ("--","-",$string);

Should remove all
if there's 3 in a row: ---
It would find the first two - and replace with one: [-]-
leaving -- which is then replaced by -

Neither has the desired behaviour.
str_replace doesn't rescan already replaced input and so --- will be matched as -, replaced by [-]-. It will not reinterpret the already replaced [-]- as .


Try this instead

preg_replace("/[-]+/", "-", $in);

This will perform greedy matches by default, matching as many consecutive -'s as it can find and replacing the whole with only one -.

Member Avatar for chrishea

Sorry, I blew that one. You could only do the str_replace if you used a while loop since it doesn't rescan. The preg_replace is definitely simpler.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.