File Sampler - sample every n rows from a file

file_sampler.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
import os

class FileSampler:

    def __init__(self):
        self.parse_args(sys.argv)

    @staticmethod
    def run():
        sampler = FileSampler()
        sampler.split()

    def split(self):

        file_number = 1
        line_number = 1
        
        for line in self.in_file:
            if line_number % self.sample_rate == 0:
                print(line.strip())
            line_number += 1

    def parse_args(self,argv):
        """parse args and set up instance variables"""
        try:
            self.sample_rate = 10
            if len(argv) > 2:
                self.sample_rate = int(argv[2])
            self.file_name = argv[1]
            self.in_file = open(self.file_name, "r")
        except:
            print self.usage()
            sys.exit(1)

    def usage(self):
        return """
        Sample every n rows from a file.

        Usage:

            $ python file_sampler.py <file_name> [sample_rate]

        sample_rate is optional (default is 10)
        """

if __name__ == "__main__":
    FileSampler.run()