How to format doubles in kdb+

Question

Is there a printf-like function in kdb q? I'm trying to format double fields to 4 digit precision. The equivalent printf formatting would be "%.04f".

Answer 1

.Q.f is probably what you're looking for:

http://code.kx.com/q/ref/dotq/#qf-format

q).Q.f[2;100]
"100.00"
q).Q.f[2;100.8888]
"100.89"