Method needed for skipping lines

Paul Hankin paul.hankin at
Thu Nov 1 01:04:51 CET 2007

On Oct 31, 5:02 pm, Gustaf <gust... at> wrote:
> Hi all,
> Just for fun, I'm working on a script to count the number of lines in source files. Some lines are auto-generated (by the IDE) and shouldn't be counted. The auto-generated part of files start with "Begin VB.Form" and end with "End" (first thing on the line). The "End" keyword may appear inside the auto-generated part, but not at the beginning of the line.
> I imagine having a flag variable to tell whether you're inside the auto-generated part, but I wasn't able to figure out exactly how. Here's the function, without the ability to skip auto-generated code:
> # Count the lines of source code in the file
> def count_lines(f):
>   file = open(f, 'r')
>   rows = 0
>   for line in file:
>     rows = rows + 1
>   return rows
> How would you modify this to exclude lines between "Begin VB.Form" and "End" as described above?

First, your function can be written much more compactly:
def count_lines(f):
    return len(open(f, 'r'))

Anyway, to answer your question, write a function that omits the lines
you want excluded:

def omit_generated_lines(lines):
    in_generated = False
    for line in lines:
        line = line.strip()
        in_generated = in_generated or line.starts_with('Begin
        if not in_generated:
             yield line
        in_generated = in_generated and not line.starts_with('End')

And count the remaining ones...

def count_lines(filename):
    return len(omit_generated_lines(open(filename, 'r')))

Paul Hankin

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