From Kx Wiki
= returns 1b if two variables are equal, and 0b if they are not. Unlike match, it operates on atoms:
q)"hello" = "world" 00010b
Also unlike match, = is not strict with regard to type:
q)1~1h 0b q)1=1h 1b
= uses comparison tolerance when matching floats:
q)(1 + 1e-13) = 1 1b
For more information, see Q for Mortals.