What does a,b = b,a do to the variable?

Question

def myfunc(a,b):
a,b = b,a ⬅️❔❔❔
if a==b and b==a:
print('Different')
elif a==b and b!=a:
print('Same')
else:
print('DifSame')
myfunc(2,3)

Python challenge by Arash

Answer 1

MrFantastic
a = 2
b = 3
a,b = b,a
print(a) #3
print(b) #2

Answer 2

Switching places.

Answer 3

MrFantastic

swapping value without using 3rd variable.

Rik Wittkopp Sorry wrong mentioned

Answer 4

A͢J
No worries buddy
😁👍

Answer 5

-> a, b = b, a
This seems simple but there are some steps involved that I think will be helpful to know.

To understand this, you need to understand two things:
1) In python, expressions are evaluated from left to right. In assignment, right hand side is evaluated first and then the left hand side.

2) You can create tuples without parentheses
x = (1,2)
y = 1, 2

both x and y above are tuples. x is created with parentheses compared to y. Whenever a value is separated by comma, it is evaluated as a tuple.
z = 1,
Here, z is also a tuple because comma.
________________________________________
Now to your question, say a = 1 and b = 2
...
-> a, b = b, a
can be written as
a, b = (b, a)

Since, right side is evaluated first, we can simplify it to:
a, b = (2, 1)

now, assignment will happen and a will be 2 and b will be 1.
this concept is known as 'tuple unpacking'. Taking the tuple on right side and assigning it to the variables on left.

For more info: https://www.w3schools.com/python/python_tuples_unpack.asp

Answer 6

Thanks everyone 😊

Answer 7

Variable value switch places, i.e they get updated