习题16 读写文件

首先给出原始的程序

from sys import argv

script ,filename = argv

print "We're going to erase %r."% filename
print "If you don't want that ,hit CTRL-C (^C)."
print "If you do want that ,hit RETURN."

raw_input("?")

print "Opening the file..."
target = open(filename, 'w')

print "Truncating the file. Goodbye!"
target.truncate()

print "Now I'm going to ask you for three lines."

line1 = raw_input("line 1: ")
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."

target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")

print "And finally ,we close it."
target.close()

这段程序就是用来写 test.txt 的，如果多次运行，由于存在 truncate命令，会擦掉以前写的东西

还有打开文件写完以后记得关闭文件

target.close()

运行结果如下



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附加练习

1

#-*-coding:utf-8-*-
from sys import argv #不解释

script ,filename = argv

print "We're going to erase %r."% filename #刚刚输入的文件名
print "If you don't want that ,hit CTRL-C (^C)."
print "If you do want that ,hit RETURN."
# 这两句话没看懂，好像想要你判断但是实际上并没有判断语句
raw_input("?")# 并没有什么卵用，纯粹是为了停顿

print "Opening the file..."
target = open(filename, 'w') # 这里的 w 其实是以 写模式 打开文件

print "Truncating the file. Goodbye!"
target.truncate()# 清空目标文件保存的内容

print "Now I'm going to ask you for three lines."

line1 = raw_input("line 1: ")#输入三行字
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."

target.write(line1)#写入
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")

print "And finally ,we close it."
target.close()#一定记得关闭文件

2.
写一个读取刚刚的test.txt 文件

其实和以前一样

3.花了好多时间

#-*-coding:utf-8-*-
from sys import argv #不解释

script ,filename = argv

print "We're going to erase %r."% filename #刚刚输入的文件名
print "If you don't want that ,hit CTRL-C (^C)."
print "If you do want that ,hit RETURN."
# 这两句话没看懂，好像想要你判断但是实际上并没有判断语句
raw_input("?")# 并没有什么卵用，纯粹是为了停顿

print "Opening the file..."
target = open(filename, 'w') # 这里的 w 其实是以 写模式 打开文件

print "Truncating the file. Goodbye!"
target.truncate()# 清空目标文件保存的内容

print "Now I'm going to ask you for three lines."

line1 = raw_input("line 1: ")#输入三行字
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."

target.write(line1+'\n'+line2+'\n'+line3)#写入

print "And finally ,we close it."
target.close()#一定记得关闭文件

print "Now we print it out:"
txt = open('test.txt')#再次打开文件，记得里面直接输入文件名是要打引号的
print txt.read()

一个  target.write() 的方法已经写在里面了，要注意换行的方法