CODEWITHSUNDEEP
python
Asif
Asif

Reputation: 1825

Check if multple variables greater than zero in python

A = 200
B = -140
C = 400
D = -260

if A < 0:
   v1 = 0
else:
   v1 = A

if B < 0:
   v2 = 0
else:
   v2 = B

 if C < 0:
   v3 = 0
else:
   v3 = C

if D < 0:
   v4 = 0
else:
   v4 = C

What is the shorthand implementation for the above code structure.? Is there a better / elegant / convenient way to do this?

Upvotes: 4

Views: 7016

Answers (4)

the wolf
the wolf

Reputation: 35522

As an alternative to mgilson's excellent answer, you could subclass int into a custom class to achieve this

>>> class V(int):
...    def __new__(cls,val,**kwargs):
...       return super(V,cls).__new__(cls,max(val,0))

Then use it directly:

>>> A=V(200)
200
>>> B=V(-140)
0
>>> [V(i) for i in [200, -140, 400, -260]]
[200, 0, 400, 0]     
>>> A,B,C,D = [V(i) for i in [200, -140, 400, -260]]

The only advantage to do it this way is you can then override __sub__ and __add__ __mul__ appropriately and then you V ints will always greater than 0 even if you have a=V(50)-100

Example:

>>> class V(int):
...    def __new__(cls,val,**kwargs):
...       return super(V,cls).__new__(cls,max(val,0)) 
...    def __sub__(self,other):
...       if int.__sub__(self,other)<0:
...         return 0
...       else:
...         return int.__sub__(self,other) 
>>> a=V(50)
>>> b=V(100)
>>> a-b                #ordinarily 50-100 would be -50, no?
0

Upvotes: 0

mgilson
mgilson

Reputation: 309831

A = 200
B = -140
C = 400
D = -260

v1, v2, v3, v4 = [x if x > 0 else 0 for x in (A, B, C, D)]

If you prefer to use the max function to the python ternary operator, it would look like:

v1, v2, v3, v4 = [max(x, 0) for x in (A, B, C, D)]

However, if you're planning on having all of these variables treated the same, you might want to consider putting them in a list/tuple in the first place.

values = [200, -140, 400, -260]
values = [max(x, 0) for x in values]

Upvotes: 13

Andy Hayden
Andy Hayden

Reputation: 375405

This can be solved easily by using the max() builtin and unpacking a list comprehension.

v1, v2, v3, v4 = [max(x, 0) for x in [a, b, c, d]]

An alternative solution is to use the map() function - this is, however, less readable:

v1, v2, v3, v4 = map(lambda x: max(x,0), [a, b, c, d])

Upvotes: 4

vinnydiehl
vinnydiehl

Reputation: 1704

Sanity check with min() and max().

v1 = max(0, A)

Upvotes: 2

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