unicode preg_replace problem in php

Question

I've got the string

$result = "bei einer Temperatur, die etwa 20 bis 60°C unterhalb des Schmelzpunktes der kristallinen Modifikation"

which comes straight from a MySQL table. The table, and the php headers are both set to UTF-8

I want to strip the 'degree' symbol: http://en.wikipedia.org/wiki/Degree_symbol and replace it with the word 'degrees' to get:

"bei einer Temperatur, die etwa 20 bis 60degreesC unterhalb des Schmelzpunktes der kristallinen Modifikation"

but I can't get it to work with preg_replace.

If I do:

$result = preg_replace('/\xB0/u'," degrees ", $result ); - I get an empty string

And if I do::

$result = preg_replace('/\u00B0/u'," degrees ", $result ); - I get the error:

Warning: preg_replace() [function.preg-replace]: Compilation failed: PCRE does not support \L, \l, \N, \U, or \u at offset 1 in /var/www/html/includes/classes/redeyeTable.inc.php on line 75

I'm not great with encodings... what am I doing wrong here?

Answer 1

Use

$result = preg_replace('/\x{00B0}/u'," degrees ", $result );

Please see here for more information on the \x{FFFF}-syntax.

It's important to note the difference between \xB0 and \x{00B0}:

• \xB0 denotes a single character with hex-code B0 (176 decimal) which is the degree symbol (°) in ISO-8859-1 for example
• \x{00B0} denotes the unicode codepoint U+00B0 which describes the degree symbol (°) in the unicode system. This codepoint will be encoded using two bytes \xC2\xB0 when using UTF-8 encoding.

Answer 2

If you use the 'u' modifier, the pattern is supposed to be treated as utf-8, so why not simply write '°' instead of '\u00B0' or '\xB0'?