Python: replace a string in a CSV file

Question

I am a beginner and I have an issue with a short code. I want to replace a string from a csv to with another string, and put out a new csv with an new name. The strings are separated with commas.

My code is a catastrophe:

import csv

f = open('C:\\User\\Desktop\\Replace_Test\\Testreplace.csv')
csv_f = csv.reader(f)

g = open('C:\\Users\\Desktop\\Replace_Test\\Testreplace.csv')
csv_g = csv.writer(g)


findlist = ['The String, that should replaced']
replacelist = ['The string that should replace the old striong']


#the function  ?:
def findReplace(find,replace):
s = f.read()
for item, replacement in zip(findlist,replacelist):
s = s.replace(item,replacement)
g.write(s)

for row in csv_f:
print(row)

f.close()
g.close()

Answer 1

You can do this with the regex package re . Also, if you use with you don't have to remember to close your files, which helps me.

EDIT: Keep in mind that this matches the exact string, meaning it's also case-sensitive. If you don't want that then you probably need to use an actual regex to find the strings that need replacing. You would do this by replacing find_str in the re.sub() call with r'your_regex_here' .

import re

# open your csv and read as a text string
with open(my_csv_path, 'r') as f:
    my_csv_text = f.read()

find_str = 'The String, that should replaced'
replace_str = 'The string that should replace the old striong'

# substitute
new_csv_str = re.sub(find_str, replace_str, my_csv_text)

# open new file and save
new_csv_path = './my_new_csv.csv' # or whatever path and name you want
with open(new_csv_path, 'w') as f:
    f.write(new_csv_str)