This does not appear to work. It is rather silly, but I wonder why this is not working properly. ⎕←'e'~⍣='Hello'

@ArbIn what behavior are you expecting?

I was testing out the power operator to do a rather silly dfn. I want to run 'Hello' ~ 'e', but until it returns 'Hllo' which is fixed. I could just run 'Hello' ~ 'e', but I wanted to use the power operator to do so.

@ArbIn Then you want 'e'~⍨⍣≡'Hello' or ~∘'e'⍣≡'Hello'

X f⍣g Y is X∘f⍣g Y

And ≡ matches the entire arguments, while = is simple-scalar-wise.

Thank you, Adam. Can you explain why do we need the swap in the first case?

The explanation is in the line below it. When ⍣ repeats the application, the left argument stays constant, and you want to remove 'e's over and over again (conceptually; once will always be enough).

Note that ~ removes the elements of the right argument from the left argument.