Jason Novinger@programming.devM to Python@programming.dev · edit-21 year ago[Meme] Swapping integers in Pythonlemmy.worldimagemessage-square17fedilinkarrow-up143arrow-down16file-textcross-posted to: bumba@boomer.casinoprogrammerhumor
arrow-up137arrow-down1image[Meme] Swapping integers in Pythonlemmy.worldJason Novinger@programming.devM to Python@programming.dev · edit-21 year agomessage-square17fedilinkfile-textcross-posted to: bumba@boomer.casinoprogrammerhumor
minus-squareHammerheart@programming.devlinkfedilinkarrow-up1·1 year agoI’m gonna need you to elaborate on this one
minus-squaredmad@programming.devlinkfedilinkarrow-up5·edit-21 year agoxor has the property x ^ x = 0, and x ^ 0 = x. So, x ^ x ^ y = y a' = a ^ b b' = b ^ a' = b ^ (a ^ b) = a a'' = (a ^ b) ^ a = b This is pretty clever, I’ve never seen this for a swap.
minus-squareActuallyRuben@actuallyruben.nllinkfedilinkarrow-up2·1 year agoCouldn’t have explained it better myself. I don’t remember where exactly I first read about this trick, but it’s mainly useful in C or Assembly, as you don’t have to resort to using a third variable/register.
![[Meme] Swapping integers in Python](https://lemmy.world/pictrs/image/8f371974-880f-47a4-838b-ff830ba9f616.png){kind=link}
I’m gonna need you to elaborate on this one
xor has the property x ^ x = 0, and x ^ 0 = x. So, x ^ x ^ y = y
a' = a ^ b b' = b ^ a' = b ^ (a ^ b) = a a'' = (a ^ b) ^ a = bThis is pretty clever, I’ve never seen this for a swap.
Couldn’t have explained it better myself. I don’t remember where exactly I first read about this trick, but it’s mainly useful in C or Assembly, as you don’t have to resort to using a third variable/register.