如何在python3中替换has_key？

Question

我尝试安装Auto-SelfControl并在执行以下命令时卡住：

sudo /usr/bin/python auto-selfcontrol.py

它显示错误：

AttributeError：'dict'对象没有属性'has_key'

我正在寻找解决方案，最后以in运算符替换has_key ，但是由于我只了解python的基础知识，因此代码对我来说非常复杂。

在3个地方使用过has_key ，您可以帮我更改它以便可以在python3上运行吗？

1。

def check_if_running(username):
""" checks if self-control is already running. """
defaults = get_selfcontrol_settings(username)
return defaults.has_key("BlockStartedDate") and not NSDate.distantFuture().isEqualToDate_(defaults["BlockStartedDate"])

2-4。

def check_config(config):
""" checks whether the config file is correct """
if not config.has_key("username"):
    exit_with_error("No username specified in config.")
if config["username"] not in get_osx_usernames():
    exit_with_error(
            "Username '{username}' unknown.\nPlease use your OSX username instead.\n" \
            "If you have trouble finding it, just enter the command 'whoami'\n" \
            "in your terminal.".format(
                    username=config["username"]))
if not config.has_key("selfcontrol-path"):
    exit_with_error("The setting 'selfcontrol-path' is required and must point to the location of SelfControl.")
if not os.path.exists(config["selfcontrol-path"]):
    exit_with_error(
            "The setting 'selfcontrol-path' does not point to the correct location of SelfControl. " \
            "Please make sure to use an absolute path and include the '.app' extension, " \
            "e.g. /Applications/SelfControl.app")
if not config.has_key("block-schedules"):
    exit_with_error("The setting 'block-schedules' is required.")
if len(config["block-schedules"]) == 0:
    exit_with_error("You need at least one schedule in 'block-schedules'.")
if config.get("host-blacklist", None) is None:
    print("WARNING:")
    msg = "It is not recommended to directly use SelfControl's blacklist. Please use the 'host-blacklist' " \
          "setting instead."
    print(msg)
    syslog.syslog(syslog.LOG_WARNING, msg)

Answer 1

尽管其他答案中的零散解决方案会起作用，但该方法存在缺陷，原因仅在于它容易犯小错误，错过需要修复的地方等。更好的解决方案是仅使用2to3转换器 。 您可以一口气修复所有文件：

$ 2to3 -f has_key -w auto-selfcontrol.py

这只能运行的has_key定影液从转换dict.has_key(key)来key in dict 。 当然，您可以自己进行修复，但是在这种情况下，简单的程序化修复程序就可以正常工作。 您可能只想在不使用-f has_key情况下运行它，以便在Py2和Py3之间应用任何其他重大更改的情况下，一次应用所有修复程序。

2to3几乎可以自动处理所有事情，但Py2 str类型更改（这是代码逻辑决定，即给定的str文字应该是Py3中的bytes还是str ）和整数除法（其中/可能需要更改为// ，基于计算是逻辑上的浮点除法还是底数除法）。 但是对于has_key ，这是非常可靠的。

Answer 2

替换如下

1。

def check_if_running(username):
""" checks if self-control is already running. """
defaults = get_selfcontrol_settings(username)
return "BlockStartedDate" in defaults and not NSDate.distantFuture().isEqualToDate_(defaults["BlockStartedDate"])

2-4。

def check_config(config):
""" checks whether the config file is correct """
if not "username" in config:
    exit_with_error("No username specified in config.")
if config["username"] not in get_osx_usernames():
    exit_with_error(
            "Username '{username}' unknown.\nPlease use your OSX username instead.\n" \
            "If you have trouble finding it, just enter the command 'whoami'\n" \
            "in your terminal.".format(
                    username=config["username"]))
if not "selfcontrol-path" in config:
    exit_with_error("The setting 'selfcontrol-path' is required and must point to the location of SelfControl.")
if not os.path.exists(config["selfcontrol-path"]):
    exit_with_error(
            "The setting 'selfcontrol-path' does not point to the correct location of SelfControl. " \
            "Please make sure to use an absolute path and include the '.app' extension, " \
            "e.g. /Applications/SelfControl.app")
if not "block-schedules" in config:
    exit_with_error("The setting 'block-schedules' is required.")
if len(config["block-schedules"]) == 0:
    exit_with_error("You need at least one schedule in 'block-schedules'.")
if config.get("host-blacklist", None) is None:
    print("WARNING:")
    msg = "It is not recommended to directly use SelfControl's blacklist. Please use the 'host-blacklist' " \
          "setting instead."
    print(msg)
    syslog.syslog(syslog.LOG_WARNING, msg)

Answer 3

该解决方案的正式资源在这里： https : //portingguide.readthedocs.io/en/latest/dicts.html

TL; DR是这样的：

some_dict.has_key('some key')

就是现在：

'some key' in some_dict

因此，在您的代码中：

return defaults.has_key("BlockStartedDate") and not NSDate.distantFuture().isEqualToDate_(defaults["BlockStartedDate"])

变为：

return "BlockStartedDate" in defaults and not NSDate.distantFuture().isEqualToDate_(defaults["BlockStartedDate"])

同样，如下行：

if not config.has_key("selfcontrol-path"):
    # do something

变得像：

if "selfcontrol-path" not in config:
    # do something

请注意，您也可以if not "selfcontrol-path" in config:编写if not "selfcontrol-path" in config:但是上面给出的示例被认为是更加Pythonic的，应该被优先使用。

Answer 4

在python3.7中测试。

   tmp = {'a':1, 'b':2, 'c':3}
   print(tmp.__contains__('a')) #True