How can I replace a consecutive multiple space to a single space, and not allow space in the beginning and end of the string?
Here is my regex
preg_match("/^([-a-z_ ])+$/i", $str)
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What do you want to do exactly, to deny or to replace? It is two different things. – Casimir et Hippolyte Apr 23 '16 at 11:18
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Deny it if it is in the beginning or end of the string, and replace it to single space if it is in the middle of the string – aronccs Apr 23 '16 at 11:19
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how many spaces do you want to remove if it is in beginning or end(if there are more than one space)? – rock321987 Apr 23 '16 at 11:30
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There should be no spaces in the beginning or end – aronccs Apr 23 '16 at 11:31
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simple solution :- `print(trim(preg_replace("/\s\s+/", " ", " ab c def ghi ")));` – rock321987 Apr 23 '16 at 11:45
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here is the link for what you need http://stackoverflow.com/questions/1981349/regex-to-replace-multiple-spaces-with-a-single-space – JYoThI Apr 23 '16 at 12:00
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Does this work for you: `"/^([a-z_\-]+[ {1})]?[a-z_\-]*)$/i"`? – Tpojka Apr 23 '16 at 12:17
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Yes, almost, but if there's only one word and an extra space, it shouldn't be accepted – aronccs Apr 23 '16 at 13:00
2 Answers
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Nothing difficult here:
if (!preg_match('~\A\s|\s\z~', $str)) {
$str = preg_replace('~\s\s+~', ' ', $str);
} // else deny
If you want to check at the same time the string only contains ascii letters, underscores, hyphens or spaces with at least one character (as in your example), you can change the first pattern to:
if (!preg_match('~\A(?:\s|\z)|[^-a-z_\s]|\s\z~i', $str)) {
Casimir et Hippolyte
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