The most recent version of this documentation can be found at https://docs.dyalog.com/20.0/.

Monadic Tilde means

Not

      ~ 0 1 0 1
1 0 1 0

Dyadic Tilde means

Without;Excluding

      3 1 4 1 5 ~ 5 1
3 4

      'aa' 'bb' 'cc' 'bb'  ~ 'bb' 'xx'
┌──┬──┐
│aa│cc│
└──┴──┘

Language Elements