replace string in file with using regular expressions [closed]

Answer 1

Here is a general format, you can either use re.sub, re.match based on your requirement. Below is a general pattern for opening a file and doing it

import re

input_file = open("input.h", "r")
output_file = open("output.h.h", "w")
br = 0
ot = 0

for line in input_file:
    match_br = re.match(r'\s*#define .*_BR (0x[a-zA-Z_0-9]{8})', line) # should be your regular expression
    match_ot = re.match(r'\s*#define (.*)_OT (0x[a-zA-Z_0-9]+)', line) # second regular expression

if match_br:
    br = match_br.group(1)
    # do something    

elif match_ot:
    ot = match_ot.group(2)    
    # do your replacement

else:
    output_file.write(line)

Answer 2

# The following code will search 'mm/dd/yyyy' (e.g. NOV/30/2016 ),
# and replace with 'mm-dd-yyyy' in multi-line mode.
import re
with open ('input.txt', 'r' ) as f:
    content = f.read()
    content_new = re.sub('(\w{2})/(\d{2})/(\d{4})', r'\1-\2-\3', content, flags = re.M)