cor (correlation verb)
Returns the correlation of its arguments as a floating point number between -1f and 1f. Perfectly correlated data results in a 1 or -1. When one variable increases as the other increases the correlation is positive; when one decreases as the other increases it is negative. Completely uncorrelated arguments return 0f. Arguments must be of the same length.
cor applies to all numeric data types and throws an error with temporal types, char and sym.
q)r:X cor Y
q)29 10 54 cor 1 3 9 0.7727746 q)10 29 54 cor 1 3 9 0.9795734 q)1 3 9 cor neg 1 3 9 -1f q)select price cor size by sym from trade
For a complete list of functions, see the kdb+ Function Reference.