Simple question

How to do this simple task in kdb? awk ‘!($1 in a){a[$0];print}’

See http://code.kx.com/wiki/Reference/BangSymbol#0N.21x

q)f:{0N!x}

q)f 1

1

1

q)f 2

2

2

q)f each 1 2 3

1

2

3

1 2 3