ex16.py

# -*- coding:utf-8 -*-

from sys import argv

script, filename = argv  #解包变量参数

print ("we're going to erase %r." % filename)
print ("if you don't want that, hit CTRL-C(^c).")   #CTRL-C的用法
print ("if you  do want that, hit RETURN.")   # RETURN的用法

input ("?")

print ("opening the file...")
target = open(filename, 'w')  #'w'的意识是‘write’，不可写成大写，否则出现语法错误。本句为定义变量target

# 学会该如何打开一个其它文件目录的文件？？？？？
#'r'       open for reading (default)
#'w'       open for writing, truncating the file first 'x'   create a new file and open it for writing
#'a'       open for writing, appending to the end of the file if it exists
#'b'       binary mode 二进制
#'t'       text mode (default) 文本模式
#'+'       open a disk file for updating (reading and writing)
#'U'       universal newline mode (deprecated)   

print ("truncating the file .Goodbye!")
#target.truncate()     #truncate()的意思是清空文件

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

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

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

target.write(line1) #write()的意思是写入文件
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")

print ("And finally,we close it.")
target.close() # 关闭文件和保存的意思