Referencing Time in Excel

[jjhmbh]

We have discovered a problem in referencing time using the LOOKUP function and I haven't been able to resolve it using VLOOKUP or the INDEX and MATCH combination

The easiest way to demonstrate the problem is to creat a list of times from 10:00 am to 12:00 pm in 15 minute increments, then copy the list into the adjacent column and convert that list into the decimal equivalent. See below for what the list should look like. I expanded the decimals to the maximum number of decimals.

10:00 0.416666666666667
10:15 0.427083333333333
10:30 0.437500000000000
10:45 0.447916666666667
11:00 0.458333333333333
11:15 0.468750000000000
11:30 0.479166666666667
11:45 0.489583333333333
12:00 0.500000000000000

Now if you write a formula using LOOKUP or VLOOKUP to try to return the decimal equivalent of a time in the left column. It works fine except at a few times like 10:45 and 11:30 when it returns the values for 10:30 and 11:15 respectively.

Any help would be appreciated.

Jeff

[Bob Phillips]

Both LOOKUP and VLOOKUP work okay for me in my (maybe limited) tests.

What data are you comparing, a time string or time value, and what formula
are you using.

--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"jjhmbh" <[email protected]> wrote in
message news:[email protected]...
>
> We have discovered a problem in referencing time using the LOOKUP
> function and I haven't been able to resolve it using VLOOKUP or the
> INDEX and MATCH combination
>
> The easiest way to demonstrate the problem is to creat a list of times
> from 10:00 am to 12:00 pm in 15 minute increments, then copy the list
> into the adjacent column and convert that list into the decimal
> equivalent. See below for what the list should look like. I expanded
> the decimals to the maximum number of decimals.
>
> 10:00 0.416666666666667
> 10:15 0.427083333333333
> 10:30 0.437500000000000
> 10:45 0.447916666666667
> 11:00 0.458333333333333
> 11:15 0.468750000000000
> 11:30 0.479166666666667
> 11:45 0.489583333333333
> 12:00 0.500000000000000
>
> Now if you write a formula using LOOKUP or VLOOKUP to try to return the
> decimal equivalent of a time in the left column. It works fine except
> at a few times like 10:45 and 11:30 when it returns the values for
> 10:30 and 11:15 respectively.
>
> Any help would be appreciated.
>
> Jeff
>
>
> --
> jjhmbh
> ------------------------------------------------------------------------
> jjhmbh's Profile:
http://www.excelforum.com/member.php...o&userid=29748
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>

[jjhmbh]

I am using LOOKUP and use the time value.

Also I am referencing the time outside of the array. If I reference the time in the array, it returns the correct value. For instance, if you use the array below

<A> <B> <C>
11:00 1 11:30
11:15 2
11:30 3
11:45 4
12:00 5

The formula LOOKUP(A3, A1:B5) returns 3
But if you reference the value outside of the table, say in cell C1, the formula returns 2.

[Nick Hodge]

It's the rounding at all those decimal places that is causing the
issue...try using the ROUND function on you lookup times, say to 6 decimals
and then wrap the looked up value in a ROUND function too using the same
decimals,like

=VLOOKUP(ROUND(A1,6),Sheet1!$A$1:$B$24,2,FALSE)

Using a little trial and error you will only be losing precision in seconds
or probably milliseconds.

One way at least if that precision is not necessary

--
HTH
Nick Hodge
Microsoft MVP - Excel
Southampton, England
www.nickhodge.co.uk
[email protected]HIS


"jjhmbh" <[email protected]> wrote in
message news:[email protected]...
>
> We have discovered a problem in referencing time using the LOOKUP
> function and I haven't been able to resolve it using VLOOKUP or the
> INDEX and MATCH combination
>
> The easiest way to demonstrate the problem is to creat a list of times
> from 10:00 am to 12:00 pm in 15 minute increments, then copy the list
> into the adjacent column and convert that list into the decimal
> equivalent. See below for what the list should look like. I expanded
> the decimals to the maximum number of decimals.
>
> 10:00 0.416666666666667
> 10:15 0.427083333333333
> 10:30 0.437500000000000
> 10:45 0.447916666666667
> 11:00 0.458333333333333
> 11:15 0.468750000000000
> 11:30 0.479166666666667
> 11:45 0.489583333333333
> 12:00 0.500000000000000
>
> Now if you write a formula using LOOKUP or VLOOKUP to try to return the
> decimal equivalent of a time in the left column. It works fine except
> at a few times like 10:45 and 11:30 when it returns the values for
> 10:30 and 11:15 respectively.
>
> Any help would be appreciated.
>
> Jeff
>
>
> --
> jjhmbh
> ------------------------------------------------------------------------
> jjhmbh's Profile:
> http://www.excelforum.com/member.php...o&userid=29748
> View this thread: http://www.excelforum.com/showthread...hreadid=494626
>

[Bob Phillips]

I think you are entering something incorrectly, as it returns 3 for me.

Is A1:A5 typed in, or a formula result? I can't get 2 no matter what I have
tried.

--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"jjhmbh" <[email protected]> wrote in
message news:[email protected]...
>
> I am using LOOKUP and use the time value.
>
> Also I am referencing the time outside of the array. If I reference
> the time in the array, it returns the correct value. For instance, if
> you use the array below
>
> <A> <B> <C>
> 11:00 1 11:30
> 11:15 2
> 11:30 3
> 11:45 4
> 12:00 5
>
> The formula LOOKUP(A3, A1:B5) returns 3
> But if you reference the value outside of the table, say in cell C1,
> the formula returns 2.
>
>
> --
> jjhmbh
> ------------------------------------------------------------------------
> jjhmbh's Profile:
http://www.excelforum.com/member.php...o&userid=29748
> View this thread: http://www.excelforum.com/showthread...hreadid=494626
>