Python Tip #87 (of 365):
Use tuple unpacking to swap references 🧵
You can use tuple unpacking to swap the values of 2 variables in Python:
x, y = y, x
Outside of feeling clever in an interview, you may NEVER need to do that... but you MIGHT need to do something similar.
Here we're swapping 2 non-variable references that don't happen to be variables:
values[-2], values[-1] = values[-1], values[-2]
That swaps the last 2 items in a sequence.
🧵 (1/2)
Or maybe you'll just reference the same variable(s) on both sides of an assignment while using tuple unpacking.
For example, here's an implementation of the Fibonacci sequence in Python:
def fibonacci():
a, b = 0, 1
while True:
a, b = b, a+b
yield a
Note that "a, b = b, a+b" assignment.
It's not quite variable swapping, but it relies on the same idea.
So while "swap 2 variables in one line" is likely pointless, the idea behind the trick does come in handy.
🧵 (2/2)
Trey Hunner 🐍