A reply to a recent question ( https://cycling74.com/forums/how-to-recognise-repetitive-numbers-on-a-message ) prompted me to read up on [zl sub], which I've never used, but it still doesn't completely make sense. Its normal function does, i.e. finding where and how many times the right list occurs in the left list.

But then there's this: "If an optional second argument is used to specify a value which will replace the number specified by the input value, the resulting list is sent out the right outlet of the zl object"

I've played around with this but can't get it happening. Could someone please explain it?

Also, does "sub" mean substitute? That'd make sense for this bit that I don't understand, but not for the main bit that I do understand.