On 12/09/2011 20:49, gry wrote:
On Sep 9, 2:04 am, Terry Reedy<tjre...@udel.edu> wrote:
On 9/8/2011 9:09 PM, papu wrote:
Hello, I have a data file (un-structed messy file) from which I have
to scrub specific list of words (delete words).
Here is what I am doing but with no result:
infile = "messy_data_file.txt"
outfile = "cleaned_file.txt"
delete_list = ["word_1","word_2"....,"word_n"]
new_file = []
fin=open(infile,"")
fout = open(outfile,"w+")
for line in fin:
for word in delete_list:
line.replace(word, "")
fout.write(line)
fin.close()
fout.close()
If you have very many words (and you will need all possible forms of
each word if you do exact matches), The following (untested and
incomplete) should run faster.
delete_set = {"word_1","word_2"....,"word_n"}
...
for line in fin:
for word in line.split()
if word not in delete_set:
fout.write(word) # also write space and nl.
Depending on what your file is like, you might be better with
re.split('(\W+)', line). An example from the manual:
>>> re.split('(\W+)', '...words, words...')
['', '...', 'words', ', ', 'words', '...', '']
so all non-word separator sequences are preserved and written back out
(as they will not match delete set).
--
Terry Jan Reedy
re.sub is handy too:
import re
delete_list=('the','rain','in','spain')
regex = re.compile('\W' + '|'.join(delete_list) + '\W')
You need parentheses around the words (I'm using non-capturing
parentheses):
regex = re.compile(r'\W(?:' + '|'.join(delete_list) + r')\W')
otherwise you'd get: '\Wthe|rain|in|spain\W'.
Even better is the word-boundary, in case there's no previous or next
character:
regex = re.compile(r'\b(?:' + '|'.join(delete_list) + r')\b')
Raw string literals are recommended for regexes.
infile='messy'
with open(infile, 'r') as f:
for l in f:
print regex.sub('', l)
--
http://mail.python.org/mailman/listinfo/python-list
