What is the syntax to compare boolean value in Python

Question

I have a code in Python 

lower={}
 for( dest in a[neigbour].keys())

    if(dest in lower.keys() == False):
        print 'false'
    }

Whenever I run this code it is not printing false. What is wrong with this code?

Answer 1

The opposite of dest in lower.keys() is dest not in lower.keys(). No need to compare to False or True.

in operator: The ‘in’ operator is used to check if a value exists in a sequence or not. Evaluates to true if it finds a variable in the specified sequence and false otherwise.

‘not in’ operator: Evaluates to true if it does not find a variable in the specified sequence and false otherwise.

In your case, this will work well - 

if (dest not in lower.keys()):