I was thinking if we were checking the boolean of string or character, we were checking if they were empty. But the following code gave me unexpected outputs.
print('0'==True)
print("0"==True)
Output:
False
False
What is happening? What we were really checking?
They are true (in a boolean context):
if '0':
print("you will see this")
if '': # for comparison
print("you will not see this")
# Alternately:
bool('0') # True
bool('') # False
But they are not equal to the special value True.
There is no contradiction.
You must be thinking of languages that convert operands to a common type before checking for equality. This is not how Python works. As you can read here, the rules for equality are pretty complex; but they boil down to this:
The default behavior for equality comparison (== and !=) is based on the identity of the objects.
So all non-empty strings are "interpreted as true" (as are most objects, other than empty containers and a couple of constants); but they are not equal to each other, and they are not equal to the constant True.
"Interpreted as true" basically means that they make a conditional come out true, and that conversion to boolean (with bool()) will give the value True.
PS. Just for fun, note that the following does hold:
>>> print(1 == True)
True
Yes, the constant True just happens to be equal to the integer 1. Why not?
if you compare this:
print('0'==False) # False
print("0"==False) # False
so they are not giving false, you are comparing if a '0' is equal to True which is false but if you are doing something like
if '0':
print("true") # this will be printed
'0' is a string, which is not empty. For strings, only empty string is falsy i.e. '':
In [239]: bool('0')
Out[239]: True
In [240]: bool('')
Out[240]: False
And for truthy/falsey test, you can just do:
if <some_value>:
no need to check against any other value. This is applicable for all types.
