I have a large vector (about 10 000 elements) and I want to make a lookup to
find a value and to put it into a grid.
My problem is that I have to make these lookups many times
(24h*60min*20=28800) into 10 000 elements vector
My data looks like this:

Station Time Stn_Time Vehicle
A 0:01 A_0:01 1
A 0:02 A_0:02 2
C 0:03 C_0:03 3
D 0:04 D_0:04 4
E 0:05 E_0:05 5
F 0:06 F_0:06 6

(tbl. 1)

i.e. for each STN and each minute I have a Vehicle. I want to present this
in a grid, where the left column contains stations and the header row
contains minutes, and in the grid inside - Vehicles:
0:01 0:02 0:03 0:04 0:05 0:06
A 1 2
B
C


(tbl.2)

To get this representation, I use VLookup function in the above grid:
=IF(ISNA(VLOOKUP($A2&"_"&B1,Sheet2!$C$2:$D$7,2,FAL SE)),"",VLOOKUP($A2&"_"&B1
,Sheet2!$C$2:$D$7,2,FALSE))
It works fine, except that it is extremely slow, because VLOOKUP function is
called around 28800 times and it looks every time into my array of 10000
elements. And it takes more than 7 minutes!!!

Is there any better way to acieve that simple task?
(I am sure it is, but I don't know it) :-(

Any suggestions are welcome

Yakimo