python核心编程--第九章 9.11 练习

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–1. 文件过滤. 显示一个文件的所有行, 忽略以井号( # )开头的行.#      这个字符被用做Python, Perl, Tcl, 等大多脚本文件的注释符号.#      附加题: 处理不是第一个字符开头的注释.import os, sysfilename = ""for filename in os.listdir(os.getcwd()):    if os.path.splitext(filename)[1] == ".py":        breakfobj = open(filename, "r")printprint '*' * 25for line in fobj:    if line[0] != '#':        print line,<pre name="code" class="python"><pre name="code" class="python">fobj.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–2. 文件访问. 提示输入数字 N 和文件 F, 然后显示文件 F 的前 N 行.import osnumber = int(raw_input("Please input the how lines to show: "))filename = raw_input("Please input the file name: ")print filenameif not os.path.exists(filename):    print "File not exist."else:    fobj = open(filename, "r")    show_number = 0    for line in fobj:        if show_number > number:            break        print line,        show_number += 1<pre name="code" class="python"><pre name="code" class="python">fobj.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–3. 文件信息. 提示输入一个文件名, 然后显示这个文本文件的总行数.import osfilename = raw_input("Please input file name: ")fobj = open(filename, "r")print len(lines = fobj.readlines())<pre name="code" class="python"><pre name="code" class="python">fobj.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–4. 文件访问. 写一个逐页显示文本文件的程序. 提示输入一个文件名, 每次显示#      文本文件的 25 行, 暂停并向用户提示"按任意键继续.", 按键后继续执行.import osfilename = raw_input("Please input file name: ")fobj = open(filename, "r")show_number = 0for f in fobj:    print f,    show_number += 1    if show_number % 25 == 0:        # print "Any key to continue..."        os.system('pause')<pre name="code" class="python">fobj.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–6. 文件比较. 写一个比较两个文本文件的程序. 如果不同, 给出第一个不同处的行号和列号.fobj1 = open("9-6.py", "r")fobj2 = open("9-3.py", "r")length = max(len(fobj1.readlines()), len(fobj2.readlines()))fobj1.seek(0)fobj2.seek(0)for linenum in range(0, length):    line1 = fobj1.readline()    line2 = fobj2.readline()    if line1 != line2:        print "diff at", linenum+1        break    else:    if len(fobj1.readlines()) == len(fobj2.readlines()):        print "same"    else:        print length+1fobj1.close()fobj2.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–13. 命令行参数#   a) 什么是命令行参数, 它们有什么用?#   b) 写一个程序, 打印出所有的命令行参数.import sysfor arg in sys.argv:    print arg

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–15. 复制文件. 提示输入两个文件名(或者使用命令行参数).#       把第一个文件的内容复制到第二个文件中去.import sysdef printhelp():    print "Useage: ", sys.argv[0], "SOURCE TARGET"    if len(sys.argv) != 3:    printhelp()else:    sourcename = sys.argv[1]    targetname = sys.argv[2]    fsource = open(sourcename, "r")    ftarget = open(targetname, "w")    for line in fsource:        ftarget.write(line)        fsource.close()    ftarget.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9–16. 文本处理. 人们输入的文字常常超过屏幕的最大宽度. 编写一个程序,#       在一个文本文件中查找长度大于 80 个字符的文本行. 从最接近 80 个#       字符的单词断行, 把剩余文件插入到下一行处.#       程序执行完毕后, 应该没有超过 80 个字符的文本行了.fsource = open("x", "r")ftarget = open("no-80.txt", "w")for line in fsource:    if len(line)-1 <= 80:        ftarget.write(line)    else:        writeline = line        while len(writeline)-1 > 80:            i = 79            while i >= 0:                if writeline[i] in [' ', ',', ':', ';', '.', '!']:                    ftarget.write(writeline[0:i+1] + '\n')                    writeline = writeline[i+1:]                    break;                i -= 1        ftarget.write(writeline)                fsource.close()ftarget.close()

#!/usr/bin/python# -*- coding: utf-8 -*-# 9.18. 搜索文件. 提示输入一个字节值(0 - 255)和一个文件名.#       显示该字符在文件中出现的次数.filename = raw_input("Please input file name: ")ch = raw_input("Please input the char for find: ")fobj = open(filename)count = 0for line in fobj:    count += line.count(ch)else:    print count