On Tuesday, June 4, 2013 11:41:43 AM UTC-4, Fábio Santos wrote: > On 4 Jun 2013 16:34, "mstagliamonte" <madm...@yahoo.it> wrote: > > > > > > On Tuesday, June 4, 2013 11:21:53 AM UTC-4, mstagliamonte wrote: > > > > Hi everyone, > > > > > > > > > > > > > > > > I am a beginner in python and trying to find my way through... :) > > > > > > > > > > > > > > > > I am writing a script to get numbers from the headers of a text file. > > > > > > > > > > > > > > > > If the header is something like: > > > > > > > > h01 = ('>scaffold_1') > > > > > > > > I just use: > > > > > > > > h01.lstrip('>scaffold_') > > > > > > > > and this returns me '1' > > > > > > > > > > > > > > > > But, if the header is: > > > > > > > > h02: ('>contig-100_0') > > > > > > > > if I use: > > > > > > > > h02.lstrip('>contig-100_') > > > > > > > > this returns me with: '' > > > > > > > > ...basically nothing. What surprises me is that if I do in this other way: > > > > > > > > h02b = h02.lstrip('>contig-100') > > > > > > > > I get h02b = ('_1') > > > > > > > > and subsequently: > > > > > > > > h02b.lstrip('_') > > > > > > > > returns me with: '1' which is what I wanted! > > > > > > > > > > > > > > > > Why is this happening? What am I missing? > > > > > > > > > > > > > > > > Thanks for your help and attention > > > > > > > > Max > > > > > > edit: h02: ('>contig-100_1') > > You don't have to use ('..') to declare a string. Just 'your string' will do. > > You can use str.split to split your string by a character. > > (Not tested) > > string_on_left, numbers = '>contig-100_01'.split('-') > > left_number, right_number = numbers.split('_') > > left_number, right_number = int(left_number), int(right_number) > > Of course, you will want to replace the variable names. > > If you have more advanced parsing needs, you will want to look at regular > expressions or blobs.
Thanks, I will try it straight away. Still, I don't understand why the original command is returning me with nothing !? Have you got any idea? I am trying to understand a bit the 'nuts and bolts' of what I am doing and this result does not make any sense to me Regards Max -- http://mail.python.org/mailman/listinfo/python-list