《笨办法学python》加分习题20——我的答案

这是我自己学习的答案，会尽力写的比较好。还望大家能够提出我的不足和错误，谢谢！

文中例题：

from sys import argvscript, input_file = argvdef print_all(f):    print f.read()def rewind(f):    f.seek(0)def print_a_line(line_count, f):    print line_count, f.readline()current_file = open(input_file)print "First let's print the whole file:\n"print_all(current_file)print "Now let's rewind, king of like a tape."rewind(current_file)print "Let's print three lines:"current_line = 1print_a_line(current_line, current_file)current_line = current_line + 1print_a_line(current_line, current_file)current_line = current_line + 1print_a_line(current_line, current_file)

运行结果：

习题答案：

1、

# -- coding: utf-8 --# 从系统中引入argvfrom sys import argv# 引入一个参量，script为脚本名称script, input_file = argv# 打印脚本fdef print_all(f):    print f.read()# 设置开始的偏移量，即从偏移位置开始运行def rewind(f):    f.seek(1)# 打印def print_a_line(line_count, f):    print line_count, f.readline()# 打开文件，将文件内容复制到current_file中current_file = open(input_file)print "First let's print the whole file:\n"print_all(current_file)print "Now let's rewind, king of like a tape."rewind(current_file)print "Let's print three lines:"current_line = 1# 传入参数current_line = 1 和文件 current_fileprint_a_line(current_line, current_file)current_line = current_line + 1print_a_line(current_line, current_file)current_line = current_line + 1print_a_line(current_line, current_file)

2、就是一步一步带进去的。
4、如一中注释

转载至： http://www.runoob.com/python/file-seek.html

感谢菜鸟教程！
5、

count = 1temp = 2count += tempprint count