使用And运算符为每个非无参数添加函数 [英] Adding Function for Every non-None Parameters with And Operator

问题描述

我想用和将具有非无参数的函数组合在一起.假设我具有此功能:
def foo(a，b，c)对于每个非参数，我想调用一个函数，例如 bar 并与 and 链接.但是，如果所有参数都不是 None ，那么在此示例中，结果将具有以下6种组合:

I want to combine functions with non-None parameters with and. Suppose I have this function:
def foo(a,b,c) For every non-None parameter, I want to call a function, for example bar and linked with and. But if all of the parameters are None, So, in the example, the result will be having 6 combinations like this:

if a is not None and b is not None and c is not None:
    return bar(a) and bar(b) and bar(c)
elif a is None and b is not None and c is not None:
    return bar(b) and bar(c)
elif a is not None and b is None and c is not None:
    return bar(a) and bar(c)
elif a is not None and b is not None and c is None:
    return bar(a) and bar(b)
elif a is None and b is None and c is not None:
    return bar(c)
elif a is None and b is not None and c is None:
    return bar(b)
elif a is not None and b is None and c is None:
    return bar(a)
else:
    return True

如何在不列出所有可能的参数组合的情况下执行此操作?例如，可以做这样的事情吗?( + = 表示和)

How do I do this without listing all of the possible combinations of parameters? For example, is it possible to do something like this? (+= symbolizes and)

func = ...
if a is not None:
    func += bar(a)
if b is not None:
    func += bar(b)
if c is not None:
    func += bar(c)
if all of them wrong:
    return True
else:
    do func

推荐答案

如果您想要并这些参数的结果，则可以使用 all()和过滤掉 None s:

If you want the result of anding these arguments, you can just use all() and filter out the Nones:

def bar(n):
    return n

def foo(a,b,c):
    return all(bar(arg) for arg in [a, b, c] if arg is not None)

foo(None, True, True)
# True

foo(False, True, None)
# False

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