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, sys
filename = ""
for filename in os.listdir(os.getcwd()):
if os.path.splitext(filename)[1] == ".py":
break
fobj = open(filename, "r")
print
print '*' * 25
for 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 os
number = int(raw_input("Please input the how lines to show: "))
filename = raw_input("Please input the file name: ")
print filename
if 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 os
filename = 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 os
filename = raw_input("Please input file name: ")
fobj = open(filename, "r")
show_number = 0
for 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+1
fobj1.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 sys
for 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 sys
def 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 = 0
for line in fobj:
count += line.count(ch)
else:
print count