《笨方法学Python》第七期：读取文件和读写文件

Python系列之笨方法学Python是我学习《笨方法学Python》—Zed A. Show著
的学习思路和理解，如有不如之处，望指出！！！

ex15 涉及两个文件：一个是ex15.py文件，一个是ex15_sample.txt文件。该文本文件的内容如下：

This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.

ex15.py 的作用就是用自己设计的脚本“打开”txt文件。

文章主要分为以下部分：

原文—摘录至《笨方法学Python》第三版

ex15.py & ex16.py

# ex15.py
from sys import argv
script,filename=argv
txt=open(filename)
print "Here's your file %r."%filename
print txt.read()
print "Type the filename again:"
file_again=raw_input('> ')
txt_again=open(file_again)
print txt_again.read()

# ex16.py

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()

应该看到的结果

---

推荐使用windows下的Powershell（命令行）

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ex15.py

> python ex15.py ex15_sample.txt
This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.

Type the filename again:
> ex15_sample.txt
This is stuff I typed into a file.
It is really cool stuff.
Lots and lots of fun to have in here.

ex16.py

> python ex16.py test.txt
We're going to erase test.txt.
If you don't want that,hit CTRL-C(^C).
If you do want that,hit RETURN.
?
Opening the file...
Truncating the file. GoodBye!
Now I'm going to ask you for three lines.
I'm going to write these to the file.
line1: Hello world
line2: Hello Python
line3: let's go!!!
I'm going to write these to the file.
And finally,we close it.

附加练习

以下摘录自原文

1. 每一行都写一下注释
2. 利用pydoc 功能查一下read()命令、write()命令、close()命令等