Python sys.argv用法详解及应用

import sys
def readfile(filename):
    f=open(filename)
    while True:
        line=f.readline()
        if len(line)==0:
            break
            print("wrong! EOF")
        print(line)
if len(sys.argv) < 2:
    print ('No action specified.')
    sys.exit()
if sys.argv[1].startswith('--'):
    option = sys.argv[1][2:]
    # fetch sys.argv[1] but without the first two characters
    if option == 'version':
        print ('Version 1.2')
    elif option == 'help':
        print ('''
This program prints files to the standard output.
Any number of files can be specified.
Options include:
  --version : Prints the version number
  --help    : Display this help''')
    else:
        print ('Unknown option.')
    sys.exit()
else:
    for filename in sys.argv[1:]:
        readfile(filename)

以上是简明python基础上摘取下来的

都好理解。

　用命令行执行你的python程序：如 python my.py --version -y

　那么 sys.argv[0]指的是 my.py

　　　 sys.argv[1]指的是--version

           sys.argv[2]指的是-y

　　　sys.argv[1]("--version")表示的是一个字符串。
　　　所以sys.argv[1][2:]就是 字符串下标为2开始的后面的字符串 就是 “version”了.


备注:  my.py 后面要改参数.  即用my.py --version -y

==================================

应用:
把字幕文件 *.VTT 批量转为 *.srt

查看了vtt和srt的区别,使用记事本打开vtt和srt,发现主要有两个

1. 首行多了 WEBVTT  标识符
2. 标点格式区别,vtt内部的"."在srt中为","

流程图:

基于python写了一个简单的脚本对其进行批量修改

• 1 引入依赖库

1. 1. os获取文件信息
   2. sys获取命令行输入args
   3. re对获取的文件内容进行匹配或更换

import os
import sys
import re

• 2 定义主函数　

• if __name__ == '__main__':
      args = sys.argv
      print(args)
  
      if os.path.isdir(args[1]):
          file_list = get_file_name(args[1], ".vtt")
          for file in file_list:
              vtt2srt(file)
  
      elif os.path.isfile(args[1]):
          vtt2srt(args[1])
      else:
          print("arg[0] should be file name or dir")

• 3 定义获取文件名称函数get_file_name

• def get_file_name(dir, file_extension):
      f_list = os.listdir(dir)
  
      result_list = []
  
      for file_name in f_list:
          if os.path.splitext(file_name)[1] == file_extension:
              result_list.append(os.path.join(dir, file_name))
      return result_list

• 4 定义转换逻辑

• def vtt2srt(file_name):
      content = open(file_name, "r", encoding="utf-8").read()
      # 删除WEBVTT行
      
      content = re.sub("WEBVTT
  
  ",'',content)
      # 替换“.”为“,”
      content = re.sub("(d{2}:d{2}:d{2}).(d{3})", lambda m: m.group(1) + ',' + m.group(2), content)
  
      output_file = os.path.splitext(file_name)[0] + '.srt'
      open(output_file, "w", encoding="utf-8").write(content)
  
  def srt2vtt(file_name):
      content = open(file_name, "r", encoding="utf-8").read()
      # 添加WEBVTT行
      
      content = "WEBVTT
  
  " + content
      # 替换“,”为“.”
      content = re.sub("(d{2}:d{2}:d{2}),(d{3})", lambda m: m.group(1) + '.' + m.group(2), content)
  
      output_file = os.path.splitext(file_name)[0] + '.vtt'
      open(output_file, "w", encoding="utf-8").write(content)

• 5 完整代码

• import os
  import sys
  import re
  
  
  def get_file_name(dir, file_extension):
      f_list = os.listdir(dir)
  
      result_list = []
  
      for file_name in f_list:
          if os.path.splitext(file_name)[1] == file_extension:
              result_list.append(os.path.join(dir, file_name))
      return result_list
  
  
  def vtt2srt(file_name):
      content = open(file_name, "r", encoding="utf-8").read()
      # 删除WEBVTT行
      
      content = re.sub("WEBVTT
  
  ",'',content)
      # 替换“.”为“,”
      content = re.sub("(d{2}:d{2}:d{2}).(d{3})", lambda m: m.group(1) + ',' + m.group(2), content)
  
      output_file = os.path.splitext(file_name)[0] + '.srt'
      open(output_file, "w", encoding="utf-8").write(content)
  
  def srt2vtt(file_name):
      content = open(file_name, "r", encoding="utf-8").read()
      # 添加WEBVTT行
      
      content = "WEBVTT
  
  " + content
      # 替换“,”为“.”
      content = re.sub("(d{2}:d{2}:d{2}),(d{3})", lambda m: m.group(1) + '.' + m.group(2), content)
  
      output_file = os.path.splitext(file_name)[0] + '.vtt'
      open(output_file, "w", encoding="utf-8").write(content)
  
      
  if __name__ == '__main__':
      args = sys.argv
  
      if os.path.isdir(args[1]):
          file_list = get_file_name(args[1], ".vtt")
          for file in file_list:
              vtt2srt(file)
  
      elif os.path.isfile(args[1]):
          vtt2srt(args[1])
          print('done')
      else:
          print("arg[0] should be file name or dir")

注意:

保存代码到trans.py
若vtt文件在d: mpvtt 文件里,
则写代码:
trans.py d: mpvtt