Output Confusion

Question

x = {1|2}|{1}|{2}
print(x)

How does this output {1,2,3}

I think the out put should be {1,2}

Answer 1

1|2, it uses a bitwise operator OR.

In binary code:
1 = 1 (to make it the same length, 01)
2 = 10
Where 0 is False, 1 is True.

It compares each bit.
01
or
10
From left to right, 0 or 1 equals 1; 1 or 0 equals 1. So it becomes 11.
11 is representing 3. (Try print(bin(3)) in playground, just ignore '0b'.)

Now x = {1|2}|{1}|{2} becomes:
x = {3} | {1} | {2} >> x = {3} union {1} union {2}
x = {1, 2, 3}

Answer 2

output - {1,2,3} is correct!

to understand better you can study about bit wise operators by solo learn community course

Answer 3

Umer ,

That's a good one. I had to think about it.

It uses two different syntactical meanings of the | symbol.

Inside the first set, | is used as the bitwise-or operator, giving the first set the value {3}.

Between sets, | is used as the union-of-sets operator. Your three sets have the unique values, {3}, {1}, and {2}, resulting in the set that is their union, {3, 1, 2}, being assigned to x.

When a set is printed, the order is not guaranteed and is implementation dependent. This implementation (Sololearn uses CPython) chose to print x in the order {1, 2, 3}.

https://docs.python.org/3/library/stdtypes.html#bitwise-operations-on-integer-types

https://docs.python.org/3/library/stdtypes.html?highlight=union#set