How can i search for pattern in string and replace it with a whitespace?

Question

- Link to the python-file | - Link to the csv testdata file

import csv 
import nltk
import re
from array import *
#Expressions
rgx_list = ['.', ',', ';', '\(', '\)', ':', '\.\.\.', '!']
#New empty array
ntitle = []
#Open a csv
with open('tripadvisor_dieburg.csv') as file:   
    reader = csv.DictReader(file)
    #Get the title and replace the expressions  
    for row in reader:
        for r in rgx_list:
            new_title = row['title']
            rgx = re.compile(r)
            new_title = re.sub(rgx, '', new_title)
        #Append to the array    
        ntitle.append(new_title)            
#Print the new title
for n in ntitle:
    print n

I created an array named rgx_list for regular expressions and i opened a csv file with content. Then i tried to replace regular expressions in the titles row['title'] with a whitespace. After that, i want to copy the new title into a new array named "ntitle".

Only '!' will be replaced in the string, but i want that all regular expressions will be replaced.
rgx_list = ['.', ',', ';', '\(', '\)', ':', '\.\.\.', '!'] Now, what i'm doing wrong?

@wilbur From the print statements, I'd guess Python 2.7 – Christian Dean Dec 09 '16 at 16:22 — Christian Dean, Dec 09 '16 at 16:22
You first "regex" means all characters. `.` should be `\.` – OneCricketeer Dec 09 '16 at 16:26 — OneCricketeer, Dec 09 '16 at 16:26

score 0 · Accepted Answer · edited May 23 '17 at 11:45

0

You've reset new_title each time over the loop.

for row in reader:
    for r in rgx_list:
        new_title = row['title']  # here - discards what you replace
        rgx = re.compile(r)
        new_title = re.sub(rgx, '', new_title)

Should instead be

for row in reader:
    new_title = row['title']  # here - only assign once
    for r in rgx_list:
        rgx = re.compile(r)
        new_title = re.sub(rgx, '', new_title)

And I think '.' should be r'\.'

You may also want to read some of the solutions at Best way to strip punctuation from a string in Python

edited May 23 '17 at 11:45

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answered Dec 09 '16 at 16:30

OneCricketeer

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Thanks, you saved my day! It's running brilliant. – expertssupervisor Dec 09 '16 at 17:05
Sure it works, i did it by accident :) Everytime i'm logged in there are a lot of messages on my screen... and sometimes i'm clicking furious anywhere... – expertssupervisor Jan 20 '17 at 13:28

How can i search for pattern in string and replace it with a whitespace?

1 Answers1