Tutorial :str.startswith() not working as I intended



Question:

I can't see why this won't work. I am performing lstrip() on the string being passed to the function, and trying to see if it starts with """. For some reason, it gets caught in an infinite loop

def find_comment(infile, line):        line_t = line.lstrip()      if not line_t.startswith('"""') and not line_t.startswith('#'):          print (line, end = '')          return line        elif line.lstrip().startswith('"""'):              while True:                  if line.rstrip().endswith('"""'):                      line = infile.readline()                      find_comment(infile, line)                  else:                      line = infile.readline()      else:          line = infile.readline()          find_comment(infile, line)  

And my output:

Enter the file name: test.txt  import re  def count_loc(infile):  

Here is the top of the file i am reading in for reference:

    import re        def count_loc(infile):          """ Receives a file and then returns the amount              of actual lines of code by not counting commented              or blank lines """            loc = 0          func_records = {}          for line in infile:          (...)  


Solution:1

You haven't provided and exit path from the recursive loop. A return statement should do the trick.

    (...)      while True:          if line.rstrip().endswith('"""'):              line = infile.readline()              return find_comment(infile, line)          else:              line = infile.readline()  


Solution:2

while True is an infinite loop. You need to break once you're done.


Solution:3

not line_t.startswith('"""') or not line_t.startswith('#')  

This expression evaluates to True no matter what string line_t denotes. Do you want 'and' instead of 'or'? Your question isn't clear to me.


Solution:4

if not line_t.startswith('"""') or not line_t.startswith('#'):  

This if will always be satisfied -- either the line doesn't start with """, or it doesn't start with # (or both). You probably meant to use and where you used or.


Solution:5

As long as lines start or end with a comment, the code below should work.

However, keep in mind that the docstrings can start or end in the middle of a line of code.

Also, you'll need to code for triple single-quotes as well as docstrings assigned to variables which aren't really comments.

Does this get you closer to an answer?

def count_loc(infile):    skipping_comments = False    loc = 0     for line in infile:      # Skip one-liners      if line.strip().startswith("#"): continue      # Toggle multi-line comment finder: on and off      if line.strip().startswith('"""'):        skipping_comments = not skipping_comments      if line.strip().endswith('"""'):        skipping_comments = not skipping_comments        continue      if skipping_comments: continue      print line,  

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