Although .I isn't too useful for code-golfing, since œ + è is basically the same (although it depends on the stack order I guess), .I is A LOT faster and therefore pretty useful sometimes. Unfortunately, it only works with lists, and for strings you'll basically have to add a leading S and trailing J.
Although
.Iisn't too useful for code-golfing, sinceœ+èis basically the same (although it depends on the stack order I guess),.Iis A LOT faster and therefore pretty useful sometimes. Unfortunately, it only works with lists, and for strings you'll basically have to add a leadingSand trailingJ.Try it online
Found in this 05AB1E answer of mine.