Count unique values within a hourly time range

[legend2009]

Hello,

I need to count how many unique "operator codes" are active within certain intervals throughout the day. I do not want to use a pivot table. I've failed trying to adapt similar formulas for date ranges. Any ideas? Sample data is below. For example, for time range 7:00 to 8:00 AM, there are 5 rows but only 3 unique "operator codes".

[TABLE="width: 306"]
<tbody>[TR]
[TD]Arrival Time[/TD]
[TD]Operator[/TD]
[/TR]
[TR]
[TD]2:30 PM[/TD]
[TD]BBB[/TD]
[/TR]
[TR]
[TD]9:47 AM[/TD]
[TD]BBB[/TD]
[/TR]
[TR]
[TD]6:45 AM[/TD]
[TD]AAA[/TD]
[/TR]
[TR]
[TD]7:34 AM[/TD]
[TD]BBB[/TD]
[/TR]
[TR]
[TD]7:47 AM[/TD]
[TD]AAA[/TD]
[/TR]
[TR]
[TD]7:50 AM[/TD]
[TD]BBB[/TD]
[/TR]
[TR]
[TD]7:32 AM[/TD]
[TD]BBB[/TD]
[/TR]
[TR]
[TD]2:27 PM[/TD]
[TD]AAA[/TD]
[/TR]
[TR]
[TD]2:32 PM[/TD]
[TD]AAA[/TD]
[/TR]
[TR]
[TD]7:45 AM[/TD]
[TD]CCC[/TD]
[/TR]
[TR]
[TD]8:45 AM[/TD]
[TD]BBB[/TD]
[/TR]
[TR]
[TD]2:37 PM[/TD]
[TD]AAA[/TD]
[/TR]
</tbody>[/TABLE]

 

[legend2009]

Just figured it out. Here is an example formula for anyone looking later:

=SUM(IF(FREQUENCY(IF(A1:A9>=TIME(7,0,0),IF(A1:A9<=TIME(8,0,0),MATCH("~"&B1:B9,B1:B9&"",0))),ROW(B1:B9)-ROW(B1)+1),1))

My times are in column A and the data is in column B.

This does require CTRL - SHIFT - ENTER.