Python Regex Find Pattern, Remove Rest of String, Write new String to File

Question

I have the codez:

import re

pattern  = ','
firstNames = "dictionary//first_names.txt"
new_file = []

def openTxtFile(txtFile):
    file = open (txtFile,"r")

data = file.read()

print (data)

file.close

def parseTextFile(textFile):

    openTxtFile(firstNames)

for line in lines:

    match = re.search(pattern, line)
        if match:

        new_line = match.group() + '\n'
        print (new_line)
        new_file.append(new_line)

with open(firstNames, 'w') as f:

f.seek(0)

f.writelines(new_file)

I am trying to take the original file, match it on a "," and return line by line to a New file the string before the "," I'm having trouble putting all this together, thanks!

Answer 1

Use the csv module, since your original file is comma separated:

import csv

with open('input_file.txt') as f:
   reader = csv.reader(f)
   names = [line[0] for line in reader]

with open('new_file.txt','w') as f:
   for name in names:
      f.write('{0}\n'.format(name))