Can anyone explain this warning?

Question

What is the meaning of of the warning?

Warning: preg_replace() [function.preg-replace]: Compilation failed: PCRE does not support \L, \l, \N{name}, \U, or \u at offset 1 in

It's being triggered by this function:

file_put_contents($file,preg_replace('(\uid=\d+)', 'uid=' . $uid, file_get_contents($file)));

Namely this pattern:

'(\uid=\d+)'

It works locally, but not online, meaning it's probably my host's version of PHP. I've tried to google a work-around, but can't find anything.

that's an invalid pattern. you forgot the delimiters, e.g. `/(\uid....`. — Marc B, Mar 12 '13 at 16:20
@Marc B: `(` and `)` are valid delimiters too AFAIK. But it prevents you from using brackets in the pattern, so it's usually not a good choice. — Fabian Schmengler, Mar 12 '13 at 16:21
@ÁlvaroG.Vicario: seesh, php needs to update their docs. text talks about brackets, but the example uses `{}`. go figure. thanks... — Marc B, Mar 12 '13 at 16:23
@fab As long as the parentheses are balanced, it's not a problem. — Barmar, Mar 12 '13 at 16:23
@MarcB The doc says "bracket style delimiters", meaning pairs of bracketing characters in general, not specifically square brackets. — Barmar, Mar 12 '13 at 16:24
@E_ERROR I won't flag it as duplicate, it's not the same error even if it is related. — Jaffa, Mar 12 '13 at 16:29

Jaffa · Accepted Answer · 2013-03-12T16:25:43.460

5

PCRE doesn't support the \u espace sequence.

In other words, your regex is not correct. Try something like (uid=\d+) instead.

As said in comments (thanks Mellamokb), here is the source.

If you want to know what is the \u, you can look here

\u Titlecase next character. Not in [ ].

edited Mar 12 '13 at 16:25

answered Mar 12 '13 at 16:20

Jaffa

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+1 Source: http://www.php.net/manual/en/reference.pcre.pattern.differences.php, #5. – mellamokb Mar 12 '13 at 16:20
Worked first time! Thanks all. – Starkers Mar 12 '13 at 16:25
@JWH You're welcome. Regex are always somewhat tricky when you're not used to them :) – Jaffa Mar 12 '13 at 16:26
@Geoffroy Yes, they are a bit fiddly! Nice when they work though :) – Starkers Mar 12 '13 at 16:28

score 0 · Answer 2 · answered Mar 12 '13 at 16:21

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file_put_contents($file,preg_replace('/uid=\d+/', 'uid=' . $uid, file_get_contents($file)));

answered Mar 12 '13 at 16:21

rationalboss

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score 0 · Answer 3 · answered Mar 12 '13 at 16:31

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RegExp pattern should be bounded by / delimiters, you can also use (# or ~). Moreover there is no escape sequence \u. You may wanna try this -

preg_replace('/\\uid=\d+/', 'uid=' . $uid, file_get_contents($file))

answered Mar 12 '13 at 16:31

ShuklaSannidhya

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Can anyone explain this warning?

3 Answers3