Interval Index Index   <<   >>
 

t are timestamps and x are the corresponding data 
u are timestamps for 5-minute intervals

   (6↑t) (¯6↑t)              (6↑u) (¯6↑u)
┌─────┬────────┐          ┌──────┬───────┐
│0 0 0│23 59 58│          │0  0 0│23 30 0│
│0 0 0│23 59 58│          │0  5 0│23 35 0│
│0 0 0│23 59 59│          │0 10 0│23 40 0│
│0 0 0│23 59 59│          │0 15 0│23 45 0│
│0 0 0│23 59 59│          │0 20 0│23 50 0│
│0 0 2│23 59 59│          │0 25 0│23 55 0│
└─────┴────────┘          └──────┴───────┘

(u⍸t) {+/⍵}⌸ x        ⍝ summary of x in 
                      ⍝ 5-minute intervals

(u⍸t) {(⍺⌷u),+/⍵}⌸ x  ⍝ 5-minute intervals &
                      ⍝ summary of x in those intervals