在 python 3.3 列表中查找最小值

Question

For example:

a=[-5,-3,-1,1,3,5]

I want to find a negative and a positive minimum.

example: negative

print(min(a)) = -5 

positive

print(min(a)) = 1

Answer 1

For getting minimum negative:

min(a)

For getting minimum positive:

min(filter(lambda x:x>0,a))

Answer 2

>>> a = [-5,-3,-1,1,3,5]
>>> min(el for el in a if el < 0)
-5
>>> min(el for el in a if el > 0)
1

Special handling may be required if a doesn't contain any negative or any positive values.

Answer 3

x = [-5,-3,-1,1,3,5]

# First min is actual min, second is based on absolute 
sort = lambda x: [min(x),min([abs(i) for i in x] )]

print(sort(x)) 

[-5, 1]

[Program finished]

Answer 4

Using functools.reduce

>>> from functools import reduce
>>> a = [-5,-3,-1,2,3,5]
>>> reduce(lambda x,y: x if 0 <= x <=y else y if y>=0 else 0, a)
2
>>> min(a)
-5
>>>

Note: This will return 0 if there are no numbers >= 0 in the list.