规范化args和kwargs为kwargs规范形式

Question

我问了一个类似的问题here关于posarg规范形式

任何可能的参数都应转换为关键字形式，根据is运算符、id或类似运算符的结果省略默认值

例如：

def myfunc(a, b=None, **kwargs):
    pass

def canonicalize(func, *args, **kwargs):
    something = inspect.signature(func)
    # Do something with args/kwargs here
    return new_args, new_kwargs

输出示例：

>>> canonicalize(myfunc, 1, 2, g=3)
(1,), {'b': 2, 'g': 3}
>>> canonicalize(myfunc, 1)
(1,), {}
>>> canonicalize(myfunc, 1, b=2)
(1,), {'b': 2}
>>> canonicalize(myfunc, 1, g=3, b=None)
(1,), {'g': 3}

Answer 1

您可以使用以下函数-基本上将具有默认值的参数移到**kwargs中的任何值中（如果它实际上没有指定给自己的默认值）：

import inspect

def canonicalize(f, *args, **kwargs):
    sig = inspect.signature(f)
    bargs = sig.bind(*args, **kwargs)
    # Pop out the named kwargs variable defaulting to {}
    ret_kwargs = bargs.arguments.pop(inspect.getfullargspec(f).varkw, {})
    # For all possible signature values
    for k, v in sig.parameters.items():
        # If the name exists in the bound arguments and has a default value
        if k in bargs.arguments and v.default is not inspect.Parameter.empty:
            # Remove from the bound arguments dict
            val = bargs.arguments.pop(k)
            # If the value isn't the same as the default value add it to ret_kwargs
            if val is not v.default:
                ret_kwargs[k] = val

    # bargs.args here will be made up of what's left in bargs.arguments
    return bargs.args, ret_kwargs