okay so it's not really smaller because it uses UTF8 also it relies on order of operations to get rid of the parens around ⍵≡'*' but
us←{('_'@(1+⍸2{(⍺≡⊃K)∧⍵≡'*'}/⍵))⍵}
is one(1) character shorter.
us←{('_'@(1+⍸2{(⍺≡⊃K)∧⍵≡'*'}/⍵))⍵}
is one(1) character shorter.
us←⊃,⍥⊆2{(⍺≡⊃K)∧⍵≡,'*':,'_'⋄⍵}/⊢ is shorter anyway
us←{'_'@{¯1⌽⍵⍷⍨(⊂⊃K),'*'}⍵} us←'_'@{¯1⌽⍵⍷⍨(⊂⊃K),'*'}You could also do: ⌽'*',⊂⊃K to save another character. I don't know if that's "better" though.