x=-i is the unary minus operator which negates the value right of it. It doesn't matter if that value is a literal (-3), a variable (-i) or a function (-f()).

x-=i is short for x = x-i, and here it's a binary subtraction, so x is set to the result of i subtracted from x.

[–] quilan@lemmy.world 2 points 3 days ago (1 children)

I need to append /s to my future silly replies I think... that said, I'll never pooh-pooh a well thought response, so thanks for the nice write-up!

[–] squaresinger@lemmy.world 2 points 3 days ago* (last edited 3 days ago)

Thanks, I totally missed your sarcasm :)

There's a couple people in this threat who seem to actually think that x = -i is some weird magic instead of a standard feature that's present in every major programming language.