Want to replace multiple occurances of # to //

Question

The transform_comments function converts comments in a Python script into those usable by a C compiler. This means looking for text that begins with a hash mark (#) and replacing it with double slashes (//), which is the C single-line comment indicator. For the purpose of this exercise, we'll ignore the possibility of a hash mark embedded inside of a Python command, and assume that it's only used to indicate a comment. We also want to treat repetitive hash marks (##), (###), etc., as a single comment indicator, to be replaced with just (//) and not (#//) or (//#). Fill in the parameters of the substitution method to complete this function.

This is my try:

import re

def transform_comments(line_of_code):
  result = re.sub(r'###',r'//', line_of_code)
  return result

print(transform_comments("### Start of program")) 
# Should be "// Start of program"
print(transform_comments("  number = 0   ## Initialize the variable")) 
# Should be "  number = 0   // Initialize the variable"
print(transform_comments("  number += 1   # Increment the variable")) 
# Should be "  number += 1   // Increment the variable"
print(transform_comments("  return(number)")) 
# Should be "  return(number)"

Answer 1

Use the * regex operator

def transform_comments(line_of_code):
  result = re.sub(r'##*',r'//', line_of_code)
  return result

from the re library docs

* Causes the resulting RE to match 0 or more repetitions of the preceding RE, as many repetitions as are possible. ab* will match a, ab, or a followed by any number of bs.