Of course there's a way :) You can use the isna function to check if a value is NA or not. There's also the dropna function which takes a DataArray as input and returns a regular Vector with the NA elements removed.
You could try something like the following: firstbreakcol = 4 lastbreakcol = 5 for i in 1:nrow(sdt2), t in sdt2[:StartTime][i]:Dates.Minute(30):sdt2[:EndTime][i] shouldprint = true for j in firstbreakcol:lastbreakcol if !isna(sdt2[i,j]) && sdt2[i,j] == t # t is in a break column shouldprint = false break end end if shouldprint println(t) end end It's a little verbose, true. I'm sure there's something cleaner with dropna, filter, etc.