Fillmore wrote:
>
> Hi, I'm trying to move away from Perl and go to Python.
> Regex seems to bethe hardest challenge so far.
>
> Perl:
>
> while (<HEADERFILE>) {
> if (/(\d+)\t(.+)$/) {
> print $1." - ". $2."\n";
> }
> }
>
> into python
>
> pattern = re.compile(r"(\d+)\t(.+)$")
> with open(fields_Indexfile,mode="rt",encoding='utf-8') as headerfile:
> for line in headerfile:
> #sys.stdout.write(line)
> m = pattern.match(line)
> print(m.group(0))
> headerfile.close()
>
> but I must be getting something fundamentally wrong because:
>
> Traceback (most recent call last):
> File "./slicer.py", line 30, in <module>
> print(m.group(0))
> AttributeError: 'NoneType' object has no attribute 'group'
>
>
> why is 'm' a None?
match() matches from the begin of the string, use search():
match = pattern.search(line)
if match is not None:
print(match.group(1), "-", match.group(2))
Also, in Python you often can use string methods instead of regular
expressions:
index, tab, value = line.strip().partition("\t")
if tab and index.isdigit():
print(index, "-", value)
> the input data has this format:
>
> :
> 3 prop1
> 4 prop2
> 5 prop3
>
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