php Replacing multiple spaces with a single space

Question

I'm trying to replace multiple spaces with a single space. When I use ereg_replace, I get an error about it being deprecated.

ereg_replace("[ \t\n\r]+", " ", $string);

Is there an identical replacement for it. I need to replace multiple " " white spaces and multiple nbsp white spaces with a single white space.

score 473 · Accepted Answer · answered Mar 03 '10 at 03:25

473

Use preg_replace() and instead of [ \t\n\r] use \s:

$output = preg_replace('!\s+!', ' ', $input);

From Regular Expression Basic Syntax Reference:

\d, \w and \s

Shorthand character classes matching digits, word characters (letters, digits, and underscores), and whitespace (spaces, tabs, and line breaks). Can be used inside and outside character classes.

answered Mar 03 '10 at 03:25

cletus

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@Cletus: This one would replace a single space with space. Don't you think something like: preg_replace('/(?:\s\s+|\n|\t)/', ' ', $x) will be more *efficient* especially on text with several single spaces ? – codaddict Mar 03 '10 at 04:23
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@codaddict: by chance, a moment ago i benchmarked those on real-life data, result (for calls on ~8300 various text articles): `/(?:\s\s+|\n|\t)/` => 1410 (slowest), `/\s+/` => 611 (ok'ish), `/\s\s+/` => 496 (fastest). The last one does not replace single `\n` or `\t`, but thats ok for my case. – Frunsi Dec 16 '11 at 02:09
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/\s{2,}/u' - if you have some UTF-8 problem add /u switch – user956584 May 28 '12 at 09:09
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for unicode there is `mb_ereg_replace` [doc](http://php.net/manual/en/function.mb-ereg-replace.php) – gondo Feb 28 '16 at 19:04
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@cletus , great work!, with keeping this regex pattern, is there a way to get rid of all spaces at the right & and the left of the string? for example, " a b c ", would be "a b c", I know we could use trim($output), but it would be nice to have it in regex – eawedat Feb 01 '17 at 22:31
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This does not work; did any of the nearly 400 people test this code with an input string that contained three or more consecutive spaces? ︎ – John Dec 07 '19 at 21:35
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This should not be correct answer, as it removes all the newlines as well, question is about spaces... – prk_001 Jan 10 '20 at 11:50
I'm not sure what the exclamation marks do but a quick Google shows that they do something like limit the number of matches. So as a previous comment says, maybe this matches a maximum of three spaces which might negate the use of +. That said, I have just tested with three and four spaces and it works correctly for me. Can anyone explain exactly what the exclamation marks do? Are they preferable to forward slashes? – Oliver P Nov 17 '20 at 12:16

score 80 · Answer 2 · edited Jan 08 '22 at 01:13

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$output = preg_replace('/\s+/', ' ',$input);

\s is shorthand for [ \t\n\r]. Multiple spaces will be replaced with single space.

edited Jan 08 '22 at 01:13

HoldOffHunger

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answered Sep 19 '13 at 06:24

Somnath Muluk

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score 52 · Answer 3 · answered Mar 03 '10 at 03:29

52

preg_replace("/[[:blank:]]+/"," ",$input)

answered Mar 03 '10 at 03:29

ghostdog74

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Doesn't replace "\n" (PHP 5.3), "/\s+/" get's job done. ;) – Marek Sep 04 '13 at 08:21
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Actually this helped, \s messed up my multibyte word, replaceing Š with some kind of square. – Mārtiņš Briedis Jun 24 '15 at 09:38
@MārtiņšBriedis There is separate multibyte function: http://php.net/manual/en/function.mb-ereg-replace.php – Juha Palomäki Oct 03 '16 at 13:03
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Unlike other answers, this command only replaces spaces (not newlines, etc...), which is exactly what is needed! Thank you so much! – itoctopus Oct 23 '19 at 12:21

php Replacing multiple spaces with a single space

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