Is there a more efficient way of replacing certain regex matches with elements?-CodePudding

I am required to use regex module. I have coded this little program to replace certain regex matches such as orange with the length of orange in # signs, for example, if orange is in the string then it will be replaced with ######.

If a string has been changed it will add " !! This string has been changed !!" to the end of the string.

If a string has not been changed but has a # in it then it will not add " !! This string has been changed !!".

I am wondering, is there a more efficient way of coding this up? using regex functions and better python code.

   orange = re.compile(r'\borange\b', re.IGNORECASE)
   frog = re.compile(r'\bfrog\b', re.IGNORECASE)
   cat = re.compile(r'\bcat\b', re.IGNORECASE)
   num = 0

   if re.search(orange, s):
      s = re.sub(orange, "!!!!!!", s)
      num  =1

   if re.search(frog, s):
      s = re.sub(frog, "!!!!", s)
      num  =1

   if re.search(cat, s):
      s = re.sub(cat, "!!!", s)
      num  =1

   if num > 0:
      return s   " !! This string has been changed !!"
   else:
      return s```

CodePudding user response：

Assuming your line input can contain 'orange' 'frog' 'cat' simultaneously ONE particular solution to this is, create a regex pattern which can match either of your solutions, then create an iterator for each match, re-place this found match with the 'x' according to the len of the matched string and printing the string modified (or not if that is the case)

Code is:

import re 
string = "orange frog cat test"
#string = "one two tree testing stackoverflow"

regex_pattern = re.compile(r"\b(orange|frog|cat)\b", re.IGNORECASE)

total_matches = regex_pattern.finditer(string)

# We find either of the options? then changes will be made
changes_done = regex_pattern.search(string) 

for match in total_matches:
    element_find = match.group(0)
    string = regex_pattern.sub("x" * len(element_find), string, 1)

if( changes_done ): 
    print(string   " | changes where made") 
else:
    print(string   " | no changes made")

What really shines in this particular solution is the third parameter of sub, where you can limit the count of matches done. As i said, one particular solution for your problem.

Output generated for the replacement will be xxxxxx xxxx xxx test | changes where made

CodePudding user response：

I guess you're using this code inside a function, since you're returning some values.

Anyway, without the num counter:

import re

pattern = r"\b(orange|frog|cat)\b"
s = "an orange eaten by a frog and a cat"

rgx_matches = re.findall(pattern, s, flags=re.IGNORECASE)
for rgx_match in rgx_matches:
    print(re.sub(rgx_match, "#"*len(rgx_match), s)  \
    " !! This string has been changed !!")