Environmental Science ：python shell 3.5.1

Just found some lambda What's interesting about expressions , Not all of them are right , Record first ：

>>> a=lambda x :x % 2
>>> a(1)
1
>>> a(0)
0

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This is the simplest lambda The expression , This means that the return value is x%2, If you change it to x%2 == 0 Returns a Boolean value , Can cooperate with filter() Use .

If we want to return something that meets certain conditions , That's what's needed ：

>>> a=lambda x:x*5 if x%2
SyntaxError: invalid syntax
>>> a=lambda x:x*5 if x%2 else None
>>> a(10)
>>> a(9)
45

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