如何在Python中除以2的列表时处理List Comprehensions中的被零除的异常 [英] How to handle the divide by zero exception in List Comprehensions while dividing 2 lists in Python

问题描述

如何在Python中除以2个列表的同时处理List Comprehensions中的被零除异常:

How to handle the divide by zero exception in List Comprehensions while dividing 2 lists in Python:

从下面的示例中:

from operator import truediv
result_list = map(truediv, [i for i in list1], [j for j in list2])

其中list2可以包含0作为值.

where the list2 can contain the 0 as value.

由于我的代码约束，我想在同一行中处理异常.请帮助我.

I want to handle the exception in the same line due to my code constrain. Please help me.

推荐答案

您不能. try是 (compound)语句 ，列表理解是 表达式 .在Python中，这些是完全不同的东西，您不能在表达式中包含一条语句.

You cannot. try is a (compound) statement, a list-comprehension is an expression. In Python these are completely distinct things and you cannot have a statement inside an expression.

您可以做的是使用包装函数:

The thing you can do is using a wrapper function:

def add_handler(handler, exc, func):
    def wrapper(*args, **kwargs):

        try:
            return func(*args, **kwargs)
        except exc:
            return handler(*args, **kwargs)    # ???
    return wrapper

然后用作:

my_truediv = add_handler(print, ZeroDivisionError, truediv)

请注意，这是非常有限.您必须返回一个值并将其插入到结果列表中，不能简单地跳过它".

Note that this is very limited. You must return a value and insert it into the resulting list, you can't simply "skip it".

您应该这样做:

from operator import truediv
result_list = []
for i, j in zip(list1, list2):
    try:
        result_list.append(i/j)
    except ZeroDivisionError:
        pass

或者，如果您只想跳过这些值，则可以将其过滤掉:

Alternatively, if you simply want to skip those values you can just filter them out:

map(lambda x_y: truediv(*x_y), filter(lambda x_y: x_y[1] != 0, zip(list1, list2)))

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