Range out of order in character class

Question

I'm getting this odd error in the preg_match() function:

Warning: preg_match(): Compilation failed: range out of order in character class at offset 54

The line which is causing this is:

preg_match("/<!--GSM\sPER\sNUMBER\s-\s$gsmNumber\s-\sSTART-->(.*)<!--GSM\sPER\sNUMBER\s-\s$gsmNumber\s-\sEND-->/s", $fileData, $matches); 

What this regular expression does is parse an HTML file, extracting only the part between:

<!--GSM PER NUMBER - 5550101 - START--> 

and:

<!--GSM PER NUMBER - 5550101 - END--> 

Do you have a hint about what could be causing this error?

Answer 1

Hi I got the same error and solved it:

  Warning: preg_match(): Compilation failed: range out of order in character class at offset <N> 

Research Phase:

.. Range out of order .. So there is a range defined which can't be used.

.. at offset N .. I had a quick look at my regex pattern. Position N was the "-". It's used to define ranges like "a-z" or "0-9" etc.

Solution

I simply escaped the "-".

 \-     

Now it is interpreted as the character "-" and not as range!

Answer 2

This error is caused for an incorrect range. For example: 9-0 a-Z To correct this, you must change 9-0 to 0-9 and a-Z to a-zA-Z In your case you are not escaping the character "-", and then, preg_match try to parse the regex and fail with an incorrect range. Escape the "-" and it must solve your problem.