Help with regular expression in python

Alain Ketterlin alain at dpt-info.u-strasbg.fr
Fri Aug 19 18:00:35 CEST 2011


Matt Funk <matze999 at gmail.com> writes:

> thanks for the suggestion. I guess i had found another way around the
> problem as well. But i really wanted to match the line exactly and i
> wanted to know why it doesn't work. That is less for the purpose of
> getting the thing to work but more because it greatly annoys me off that
> i can't figure out why it doesn't work. I.e. why the expression is not
> matches {32} times. I just don't get it.

Because a line is not 32 times a number, it is a number followed by 31
times "a space followed by a number". Using Jason's regexp, you can
build the regexp step by step:

number = r"\d\.\d+e\+\d+"
numbersequence = r"%s( %s){31}" % (number,number)

There are better ways to build your regexp, but I think this one is
convenient to answer your question. You still have to append what will
match the end of the line.

-- Alain.

P/S: please do not top-post

>> $ python
>> Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)
>> [GCC 4.4.3] on linux2
>> Type "help", "copyright", "credits" or "license" for more information.
>>>>> data
>> '1.002000e+01 2.037000e+01 2.128000e+01 1.908000e+01 1.871000e+01
>> 1.914000e+01 2.007000e+01 1.664000e+01 2.204000e+01 2.109000e+01
>> 2.209000e+01 2.376000e+01 2.158000e+01 2.177000e+01 2.152000e+01
>> 2.267000e+01 1.084000e+01 1.671000e+01 1.888000e+01 1.854000e+01
>> 2.064000e+01 2.000000e+01 2.200000e+01 2.139000e+01 2.137000e+01
>> 2.178000e+01 2.179000e+01 2.123000e+01 2.201000e+01 2.150000e+01
>> 2.150000e+01 2.199000e+01 : (instance: 0)       :       some
>> description'
>>>>> import re
>>>>> re.findall(r"\d\.\d+e\+\d+", data)
>> ['1.002000e+01', '2.037000e+01', '2.128000e+01', '1.908000e+01',
>> '1.871000e+01', '1.914000e+01', '2.007000e+01', '1.664000e+01',
>> '2.204000e+01', '2.109000e+01', '2.209000e+01', '2.376000e+01',
>> '2.158000e+01', '2.177000e+01', '2.152000e+01', '2.267000e+01',
>> '1.084000e+01', '1.671000e+01', '1.888000e+01', '1.854000e+01',
>> '2.064000e+01', '2.000000e+01', '2.200000e+01', '2.139000e+01',
>> '2.137000e+01', '2.178000e+01', '2.179000e+01', '2.123000e+01',
>> '2.201000e+01', '2.150000e+01', '2.150000e+01', '2.199000e+01']



More information about the Python-list mailing list