Ndtyjky

A solution for the Python 3

Code:

# variable lst is your sequence

min(filter(lambda x: x is not None, lst)) if any(lst) else None

Examples:

In [3]: lst = [None, 1, None]



In [4]: min(filter(lambda x: x is not None, lst)) if any(lst) else None

Out[4]: 1



In [5]: lst = [-4, None, 11]



In [6]: min(filter(lambda x: x is not None, lst)) if any(lst) else None

Out[6]: -4



In [7]: lst = [0, 7, -79]



In [8]: min(filter(lambda x: x is not None, lst)) if any(lst) else None

Out[8]: -79



In [9]: lst = [None, None, None]



In [10]: min(filter(lambda x: x is not None, lst)) if any(lst) else None



In [11]: print(min(filter(lambda x: x is not None, lst)) if any(lst) else None)

None

Notes:

Worked in sequence presents as numbers as well as None. If all values is None min() raise exception

ValueError: min() arg is an empty sequence

This code resolve this problem at all

Pros:

1. Worked if None presents in sequence


2. Worked on Python 3


3. max() will be work also

Cons

1. Need more than one non-zero variable in the list. i.e. [0,None] fails.


2. Need a variable (example lst) or need duplicate the sequence

Here is an inline decorator that you can use to filter out None values that might be passed to a function:

noNones = lambda fn : lambda *args : fn(a for a in args if a is not None)

print noNones(min)(None, 3)

print noNones(max)(None, 3)

prints:

3

3

def max_none(a, b):

    if a is None:

        a = float('-inf')

    if b is None:

        b = float('-inf')

    return max(a, b)



def min_none(a, b):

    if a is None:

        a = float('inf')

    if b is None:

        b = float('inf')

    return min(a, b)



max_none(None, 3)

max_none(3, None)

min_none(None, 3)

min_none(3, None)

You can use an inline if and an infinity as the default, as that will work for any value:

a = max(a if a is not None else float('-inf'), 3)

b = min(b if b is not None else float('inf'), 3)

My solution for Python 3 (3.4 and greater):

min((x for x in lst if x is not None), default=None)

max((x for x in lst if x is not None), default=None)

a=max(a,3) if a is not None else 3

b=min(b,3) if b is not None else 3

@utdemir's answer works great for the provided example but would raise an error in some scenarios.

One issue that comes up is if you have a list with only None values. If you provide an empty sequence to min(), it will raise an error:

>>> mylist = [None, None]

>>> min(value for value in mylist if value)

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

ValueError: min() arg is an empty sequence

As such, this snippet would prevent the error:

def find_minimum(minimums):

    potential_mins = (value for value in minimums if value is not None)

    if potential_mins:

        return min(potential_mins)