CharacterSwapping←{
⍝ Swap elements of ⍺ from (1 to c) and (o+1 to o+c)
     ⍺←'PerlWeeklyChallenge'
     ⎕IO←0
     n←≢⍺
     (c o)←⍵
     si←n|1+⍳c
     ri←n|1+o+⍳c
     s[ri]@si⊢s[si]@ri⊢⍺
 }