Replace certain words in a text file

Question

I am trying to replace specific words within a text file. I have a text file (test.txt) the content of the file is as follows:

red red blue
green red blue
red

I wish to replace each instance of red with RED in capitals.

My coding so far is this:

print "What file would you like to read?",
filename = raw_input()

txt = open(filename)
print txt.read()

import re

x=len(re.findall('red', open(filename).read()))

print "The total number of the word 'red' is: %r" % x

I really have no idea how I would go about replacing words and i'm sure my current attempt at just counting the word is bad. I would appreciate any help.

You can try `txt.read().replace("red","RED")` assuming you dont have any words containing red — Ashoka Lella, Jul 03 '14 at 10:24

score 1 · Accepted Answer · answered Jul 03 '14 at 10:25

1

If you want to replace the content in file, you can try this

content = []
filename='foo.txt'
with open(filename, 'r') as read_file:
    content = read_file.readlines()

with open(filename, 'w') as write_file:
    for line in content:
        write_file.write(line.replace("red", "RED"))

answered Jul 03 '14 at 10:25

xecgr

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2

This will change `the red redirect link` to `the RED REDirect link`. – Burhan Khalid Jul 03 '14 at 10:41
@BurhanKhalid My answer solves it, if that is an issue for the OP – Germano Jul 03 '14 at 10:42

score 0 · Answer 2 · answered Jul 03 '14 at 10:30

For this kind of problem fileinput is right place

import fileinput
import sys
count = 0
for line in fileinput.input(["a.txt"], inplace=True, backup='.bak'):
    if 'red' in line:
        no_of_red=line.count('red')
        sys.stdout.write(line.replace('red','RED'))
        count += no_of_red
    else:
        sys.stdout.write(line)

print "The total number of the word 'red' is: %r" % count

Germano · Answer 3 · 2014-07-03T10:50:31.153

To avoid replacing not isolated instance of red such as in redness you should use a regular expression

import re
pattern = re.compile(r'\bred\b')

print "What file would you like to read?",
filename = raw_input()

with open(filename, 'r') as f:
    content = f.read()
    replaced_content, count = pattern.subn('RED', content)

For example, for a file containing

the red redirect link

the output is:

replaced_content
>>> 'the RED redirect link'
count
>>> 1

Replace certain words in a text file

3 Answers3