将长列表格式化为80列

Question

  try:
    for key in copy['KnownNetworks'].keys():
      if copy['KnownNetworks'][key]['SSID_STR'] == networkDict['name']:
        networkDict['uuid'] = copy['KnownNetworks'][key]['Unique Password ID']
        print 'Found existing reference to wireless password uuid: %s' % networkDict['uuid']
        found = True
  except:
    print 'Key KnownNetworks not found'
  # Clean up top level key

  keychain = '/Library/Keychains/System.keychain'
  arguments = [security,"add-generic-password",'-a',networkDict['name'],'-l',networkDict['name'],'-D','Airport network password','-s',networkDict['uuid'],'-w',networkDict['pass'],'-T','group://Aiport','-T','/System/Library/CoreServices/SystemUIServer.app','-T','/Applications/System Preferences.app','-T','/usr/libexec/airportd',keychain]
  addKeychainPassword(arguments)
  users = '/var/db/dslocal/nodes/Default/users'
  listing = os.listdir(users)
  for plist in listing:

我有个格式化的问题，上面的例子中，是否有更好的方式来格式化参数列表的声明？这是一个子进程调用，所以我需要它是一个列表，但我想我可以把它转换成字典再转换回列表。我的主要目标是希望它能符合大多数Unix脚本的80列标准。你有什么技巧可以分享，让代码看起来更整洁吗？

Answer 1

对于超过80个字符的代码行，你可以把它们分成多行。这里很简单，因为你有一个列表。

arguments = [security,
             'add-generic-password',
             '-a', networkDict['name'],
             '-l', networkDict['name'],
             '-D', 'Airport network password',
             '-s', networkDict['uuid'],
             '-w', networkDict['pass'],
             '-T', 'group://Aiport',
             '-T', '/System/Library/CoreServices/SystemUIServer.app',
             '-T', '/Applications/System Preferences.app',
             '-T', '/usr/libexec/airportd',
             keychain]

这样做不仅让你感到遵循Python风格指南的满足感，而且当代码这样格式化时，看到传递的参数会容易得多。

关于Python代码布局的官方指南是PEP-8。里面还有其他关于如何拆分长代码行的例子。