Scott David Daniels wrote:
> pyluke wrote:
>> I'm parsing LaTeX document and want to find lines with equations blocked
>> by "\[" and "\]", but not other instances of "\[" like "a & b & c \\[5pt]"
>> so, in short, I was to match "\[" but not "\\]" .... I've tried:
>> check_eq = re.compile('(?!\%\s*)\\\\\[')
> > check_eq.search(line)
> > this works in finding the "\[" but also the "\\["
>
> If you are parsing with regular expressions, you are running a marathon.
> If you are doing regular expressions without raw strings, you are running
> a marathon barefoot.
>
> Notice: len('(?!\%\s*)\\\\\[') == 13
> len(r'(?!\%\s*)\\\\\[') == 15
>
>> so I would think this would work
>> check_eq = re.compile('(?![\%\s*\\\\])\\\\\[')
>> check_eq.search(line)
>>
>> but it doesn't. Any tips?
> Give us examples that should work and that should not (test cases),
> and the proper results of those tests. Don't make people trying to
> help you guess about anything you know.
>
> --Scott David Daniels
> [EMAIL PROTECTED]
To add to what scott said, two advices:
1. Use Kodos, it's a RE debugger and an extremely fine tool to generate
your regular expressions.
2. Read the module's documentation. Several time. In your case read the
"negative lookbehind assertion" part "(?<! ... )" several time, until
you understand how it may be of use to you.
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