LPTHW 笨办法学python 20章

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from sys import argv
script, input_file = argv
def print_all(f):
    print f.read()
def rewind(f):
    global line_no
    f.seek(0, 0)
    line_no = 1
def print_a_line(line_count,f):
    global line_no
    line_count = line_no
    print line_count,f.readline()
    line_no += 1

current_file = open(input_file)
print "First let‘s print the whole file:\n"
print_all(current_file)

print "Now let‘s rewind, kind of like a tape."
rewind(current_file)

print "Let‘s print three lines:"
for i in xrange(3):
    print_a_line(line_no,current_file)