python 笔记 读写文件——12.26

今天很开心，发现csdn可以直接发代码，之前一直羡慕别人可是不会发。

习题 16:  读写文件

目标与感悟：

• close –  关闭文件。跟你编辑器的 文件 -> 保存 ..  一个意思。

• read–  读取文件内容。你可以把结果赋给一个变量。

•readline –  读取文本文件中的一行。

•truncate –  清空文件，请小心使用该命令。

• write(stuff) –  将 stuff 写入文件

 

 

ex16.py

#-*- coding:utf-8-*-from sys import argv script,filename = argv #这里提示到的CTRL-C和再次敲击RETURN应该是内置的，我并没有看到定义。print "We're going to erase %r." % filenameprint "If you don't want that, hit CTRL-C (^C)."print "If you do want that, hit RETURN." raw_input("?") print "Opening the file..."#这里使用了open，open(路径+文件名,读写模式)#读写模式可以分为：r 只读，r+读写，w新建（会覆盖原有文件）#a追加，b二进制#常用模式'rb','wb','r+b'target = open(filename, 'w') print "Truncating the file. Goodbye!"#truncate,我感觉多余了，因为oepn的参数w就有新建覆盖的意思target.truncate() print "Now I'm going to ask you for three lines." #让用户输入3个句子，并将其赋予给3个变量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." #将3个变量写入文件中，并且每写完一个换行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()

运行结果:

test.txt

It's a good day!

How are you?

I need to shave itoff.

 

 

 

 

感悟与自我测试:

 

ex16_1.py

#-*-coding: utf-8-*-from sys import argv script, filename = argv print "Let's go to test!"print "Now,erase the %r." %filenameprint "If you don't want that, hit CTRL-C (^C)."print "If you do want that, hit RETURN." raw_input(">???") #此处的路径需要多加一个\，因为python中的\另有用处，所以需要转义。print "In \test\,creating and opening the file..."target = open('C:\\Users\\gyl\\test\\test1\\%s'%filename,'w')  #我感觉没必要，所以先令其失效，事后也证明是对的。#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("Continue line 2:") print "I'm going to write these to the file." #此处我并没有在第二行之后进行换行，所以应该是只有2行target.write(line1)target.write("\n")target.write(line2)target.write(line3) print "And finally, we close it." #close，很容易理解就是关闭的意思。target.close()

运行结果:

 

test.txt

This is the firstline!

This is the secondline!This is also second line!