number_lines.py

import os
import fnmatch

def Walk(root='.', recurse=True, pattern='*'):
    """
        Generator for walking a directory tree.
        Starts at specified root folder, returning files
        that match our pattern. Optionally will also
        recurse through sub-folders.
    """
    for path, subdirs, files in os.walk(root):
        for name in files:
            if fnmatch.fnmatch(name, pattern):
                yield os.path.join(path, name)
        if not recurse:
            break

def LOC(root='PythonProgram/', recurse=True):
    """
        Counts lines of code in two ways:
            maximal size (source LOC) with blank lines and comments
            minimal size (logical LOC) stripping same

        Sums all Python files in the specified folder.
        By default recurses through subfolders.
    """
    count_mini, count_maxi = 0, 0
    for fspec in Walk(root, recurse, '*.py'):
        print(fspec)
        skip = False
        for line in open(fspec).readlines():
            count_maxi += 1

            line = line.strip()
            if line:
                if not skip:
                    count_mini += 1

    return count_mini, count_maxi

print("Number of lines in PythonProgram: {0[0]} minimum, {0[1]} maximum".format(LOC()))