Python sys.argv用法詳解及應用

 

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)

 

以上是簡明python基礎上摘取下來的

都好理解。

　用命令行執行你的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")表示的是一個字符串。
　　　所以sys.argv[1][2:]就是 字符串下標為2開始的后面的字符串 就是 “version”了.


備注:  my.py 后面要改參數.  即用my.py --version -y

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

應用:
把字幕文件 *.VTT 批量轉為 *.srt

查看了vtt和srt的區別,使用記事本打開vtt和srt,發現主要有兩個

 

1. 首行多了 WEBVTT\n\n 標識符
2. 標點格式區別,vtt內部的"."在srt中為","

流程圖:

 

 

基於python寫了一個簡單的腳本對其進行批量修改

 

• 1 引入依賴庫

1. 1. os獲取文件信息
   2. sys獲取命令行輸入args
   3. re對獲取的文件內容進行匹配或更換

import os
import sys
import re

• 2 定義主函數　

• 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 定義獲取文件名稱函數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 定義轉換邏輯

• def vtt2srt(file_name):
      content = open(file_name, "r", encoding="utf-8").read()
      # 刪除WEBVTT行
      
      content = re.sub("WEBVTT\n\n",'',content)
      # 替換“.”為“,”
      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\n\n" + content
      # 替換“,”為“.”
      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 完整代碼

• 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()
      # 刪除WEBVTT行
      
      content = re.sub("WEBVTT\n\n",'',content)
      # 替換“.”為“,”
      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\n\n" + content
      # 替換“,”為“.”
      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:

保存代碼到trans.py
若vtt文件在d:\tmp\vtt 文件里,
則寫代碼:
trans.py d:\tmp\vtt