I am learning python, but I\'m a bit confused by the following result.
In [41]: 1 == True
Out[41]: True
In [42]: if(1):
...: print(\'111\')
...:
Any object can be tested for "truthiness":
Any object can be tested for truth value, for use in an if or while condition or as operand of the Boolean operations below. The following values are considered false:
None
False
zero of any numeric type, for example, 0, 0.0, 0j.
any empty sequence, for example, '', (), [].
any empty mapping, for example, {}.
instances of user-defined classes, if the class defines a bool() or len() method, when that method returns the integer zero or bool value False. [1]
All other values are considered true — so objects of many types are always true.
Operations and built-in functions that have a Boolean result always return 0 or False for false and 1 or True for true, unless otherwise stated. (Important exception: the Boolean operations or and and always return one of their operands.)
So it's not hard to see that if ...
will enter the branch. The Ellipsis
object is considered true
. However that doesn't mean it has to be equal to True
. Just the bool(...) == True
!
The if
will implicitly call bool
on the condition, so:
if ...:
# something
will be evaluated as if you had written:
if bool(...):
# something
and:
>>> bool(...)
True
>>> bool(1)
True
>>> bool(2)
True
However there's one catch here. True
is equal to 1
and False
equal to 0
, but that's just because bool
subclasses int
eger in python.