Normalize spaces in a string?

Question

I need to normalize the spaces in a string:

Remove multiple adjacent spaces
Remove spaces at the beginning and end of the string

E.g. " my name is " => my name is

I tried

str_replace('  ',' ',$str);

I also tried php Replacing multiple spaces with a single space but that didn't work either.

The RegExp solution you linked seems like a fine solution. Why do you think it's not helpful to you? — Halcyon, Feb 25 '13 at 16:19
***How*** is that referenced question ***not*** helpful for your needs? — Kermit, Feb 25 '13 at 16:19
i also want to remove space before and after string.. referenced code remove duplicate spaces and its different from my question — Rahul R, Feb 25 '13 at 16:20
didn't you tried any one? preg_replace("/[[:blank:]]+/"," ",$input) — , Feb 25 '13 at 16:21
possible duplicate of [php Replacing multiple spaces with a single space](http://stackoverflow.com/questions/2368539/php-replacing-multiple-spaces-with-a-single-space) — Waleed Khan, Feb 25 '13 at 16:23

Sammitch · Answer 1 · 2013-02-25T16:27:23.793

14

Replace any occurrence of 2 or more spaces with a single space, and trim:

$str = preg_replace('/ {2,}/', ' ', trim($input));

Note: using the whitespace character class \s here is a fairly bad idea since it will match linebreaks and other whitespace that you might not expect.

edited Feb 25 '13 at 16:27

answered Feb 25 '13 at 16:22

Sammitch

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Don't forget OP needs to trim spaces at the beginning and end of line. Updated the answer :) Also, if the real task is to replace all "whitespace" symbols: space, tab, vertical tab (anybody seen that ever?), etc. use `\s` instead of just ` ` – J0HN Feb 25 '13 at 16:25

score 0 · Answer 2 · answered Feb 25 '13 at 16:22

0

Use a regex

$text = preg_replace("~\\s{2,}~", " ", $text);

answered Feb 25 '13 at 16:22

Philipp

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score 0 · Answer 3 · edited May 23 '17 at 12:17

The \s approach strips away newlines too, and / {2,}/ approach ignores tabs and spaces at beginning of line right after a newline.

If you want to save newlines and get a more accurate result, I'd suggest this impressive answer to similar question, and this improvement of the previous answer. According to their note, the answer to your question is:

$norm_str = preg_replace('/[^\S\r\n]+/', ' ', trim($str));

In short, this is taking advantage of double negation. Read the links to get an in-depth explanation of the trick.

Normalize spaces in a string?

3 Answers3