On 2009-07-24, amr...@iisermohali.ac.in <amr...@iisermohali.ac.in> wrote: > > Hi, > > I have a file having lines:- > > 48 ALA H = 8.33 N = 120.77 CA = 55.18 HA = 4.12 C = 181.50 > 104 ALA H = 7.70 N = 121.21 CA = 54.32 HA = 4.21 C = > 85 ALA H = 8.60 N = CA = HA = 4.65 C = > > Now i want to make two another file in which i want to put > those lines for which C is missing and another one for which > N,CA and C all are missing, > > I tried in this way: > import re > f = open('chem.txt') > for line in f: > if re.search('C = ',''): > print line > > but i am not getting the desired output.
I've told you before: don't use regular expressions (e.g. the "re" module). Stop using regular expressions now. Regular expressions are way beyond your capabilities. Use simple operations like split() and "in": f = open('chem.txt') for line in f: if "C = " in line: print line You really need to work through a Python tutorial or two: http://docs.python.org/tutorial/ http://www.greenteapress.com/thinkpython/thinkpython.html Better yet, take an couple introductory programming courses. I'm a bit surprised that one could become a "Research Fellow" in a scientific field without taking any programming courses. -- Grant Edwards grante Yow! I'm also against at BODY-SURFING!! visi.com -- http://mail.python.org/mailman/listinfo/python-list