pyhton 零起点(3)

每次用vim 都要:set nu 挺麻烦的 干脆就直接设置配置文件了 vi ~/.vimrc  添加set nu  就不用那么麻烦了

读取文件

# linux.txt 文本里面有三行字
from sys import argv

script, filename = argv
#打开文件
txt = open(filename)

print "Here's your file %r: " % filename
print txt.read() #输出文本内容
#raw_input打开
print "Type the filename again: "
filename_again = raw_input("> ")
txt_gagin = open(filename_again)
print txt_again.raed() 

读写文件

• 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。

  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()

  ：自己测试了一下target = open(filename, 'w') 用了'w'模式 不需要target.truncate()效果也是一样的 尝试了一下'w'去掉 发现出错了File not opening for writing
  复制一个文件的内容到另一个文件

  from sys import argv
  from os.path import exists
  
  script, from_file, to_file = argv
  
  print "Copying from %s to %s" % (from_file, to_file)
  
  # we could do these two on one line too, how?
  in_file = open(from_file)
  indata = in_file.read()
  
  print "The input file is %d bytes long" % len(indata)
  #判断文件是否存在
  print "Does the output file exist? %r" % exists(to_file)
  print "Ready, hit RETURN to continue, CTRL-C to abort."
  raw_input()
  
  out_file = open(to_file, 'w')
  out_file.write(indata)
  
  print "Alright, all done."
  
  out_file.close()
  in_file.close()
   

  ：有一个奇怪的问题就是 你的to_file里面的原本内容会被清除