what is the meaning of the line 1 ?

Question

if not True:
print("1")
elif not (1 + 1 == 3):
print("2")
else:
print("3")

Answer 1

Conditions in Python evaluate as True or False.

Normally you first ask a question:

if x < 5:
....

And depending on what x is, the if block will be executed or not.

Sometimes you want a condition to always be True, for example in an eternal loop:

while True:
...

True is always True, so the loop will run and run and run.

while not True:
....

could be translated to while True is not True:

And that is never, because True is always True, so the answer is False and the loop will not be executed.

Same with

if not True:
....

it's dead code, basically.

I hope this wasn't too confusing. 🙄😉

Answer 2

First if will never executed as always is false.

Answer 3

thanks to all

Answer 4

The if construction is like a door.
True means that the door is open and you can enter inside (in the if construction block).
False - the door is closed.

With 'not True' you have always False.
So, True and False are not supposed to be used literally in the if constructions. You should use real conditions:
x = 5
y = 9

if (x > y): # (5 > 9 = False)
print("x > y")
else if x < y: # (5 < 9 = True)
print("x < y") # We enter here
else: # (all above = False)
print("x = y")

is_greater_y = y > x # (True)

if is_greater_y: # True
print("y > x") # We enter here
else:
print("y <= x")

if not (x >= y): # True
print("x < y")
else:
print("x >= y")