Hello
In the following expression
exp = HoldForm[#1^2 "+"] & /@ {4, 1, 7}
I want to remove the last "+". Its position I get with:
pos = Last[Position[exp, "+"]]
I know it's correct because :
exp[[##]] & @@ pos == "+" (* True*)
But
exp[[##]] & @@ pos = ""
will not work. I cannot understand it since
exp[[3, 1, 2]] = ""
works OK.
Please explain what is going on ? Thanks