CODEWITHSUNDEEP
pythonif-statement
Decro
Decro

Reputation: 1

How can i test two Variables on NoneType in Python 3?

All the time I tried to compare two variables with type None but it doesn't work.

example:

if type(a and b) == type(None):
   #do something
else:
   #do other stuff

Does somebody know the right statement and an explanation?

Upvotes: 0

Views: 1147

Answers (3)

ramanand sagar
ramanand sagar

Reputation: 1

def nonetype_check1(a,b):
    if a==b and a==None:           
        print(" both are nonetype type",type(a))
    elif a!=b:
        print("values of both are not same",a,b)
    else:
        print("values of both are same but not nonetype",type(b),type(b))

output: 1)a=Nonetype,b=Nonetype,answer:both are nonetype type 2)a=Nonetype,b=3, answer:values of both are not same None 3 3)a=3,b=3, answer:values of both are same but not nonetype

Upvotes: 0

Alt
Alt

Reputation: 1

In Python, if you want to check for null variables, you should use the x is None syntax. There is only one instance of the None object in a Python runtime (it's called a singleton). Moreover, checking against type tends to be bad practice in general. In your case, you should do:

if a is None and b is None:
   #do something
else:
   #do other stuff

You can also simplify it to if (a and b) is None, since the and operator will propagate the None if one of a and b is None.

Upvotes: 0

Rahul K P
Rahul K P

Reputation: 16081

You can check differently.

if a is None and b is None:
    print('Both a and b are None')
else:
    print('a and b are not None')

Issues with your code.

  1. a and b will return either a or b
  2. type comparison is not a good option.

Upvotes: 2

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