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  #1  
Old 07-20-2009, 02:31 PM
Mel_P Mel_P is offline
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Red face Selecting every nth (e.g. 10th) row for a graph

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Hello,

I have too many data points (time, value) for a graph.

I want to select every 10th or 20th point to plot. Any ideas how I can achieve this please.

I have tried selection
row 1
row 10
row 20

and extending it but this then selects 2, 11, 21 !!

Help please !!

Thanks, Mel
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  #2  
Old 07-20-2009, 02:38 PM
zero760 zero760 is offline
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Re: Selecting every nth (e.g. 10th) row for a graph

Press the CTRL key and then highlight the data points. Excel should
pick up the fields you want.
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Old 07-20-2009, 05:01 PM
Mel_P Mel_P is offline
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Re: Selecting every nth (e.g. 10th) row for a graph

But I have 33,000 rows! So manual selection is out.

I am trying to do this:

row1>>>>>>>>link>>>>>>>>>row 1 (time, value)
row2>>>>>>>>>>>>>>>>>>>row10(time, value)
..>>>>>>>>>>>>>>>>>>>>>row20 (time, value)
row10
..
..
row20

so that I can easily graph the row1, row10, row20 pairs as they form a contiguous dataset I can lasoo.

Last edited by Mel_P; 07-20-2009 at 05:06 PM.
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Old 07-20-2009, 05:15 PM
Mel_P Mel_P is offline
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plotting every 20th (say) value from 33,000 points

I have 33,000 pairs of values from a logger.

-Time, concentration

How do I plot (or extract) every 20th pair of value (or some other defined interval)?

Any ideas please (macro, VBA NOT manual selection)

Thanks. Mel
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  #5  
Old 07-20-2009, 06:35 PM
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shg shg is offline
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shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay shg makes giving solutions look like childsplay
Re: Selecting every nth (e.g. 10th) row for a graph

Threads merged -- there's no need to start a new one. Carry on.
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Old 07-20-2009, 06:56 PM
Mel_P Mel_P is offline
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Re: Selecting every nth (e.g. 10th) row for a graph

Thanks mod - apols.
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Old 07-20-2009, 07:15 PM
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Re: Selecting every nth (e.g. 10th) row for a graph

Any reason not to do this with a simple formula?

If you really want code, post a workbook that shows input (not all 30000 rows) and desired output (like, where it goes).
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Old 07-21-2009, 04:45 PM
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Re: Selecting every nth (e.g. 10th) row for a graph

Posted it on microsoft excel forum and a response telling me to use the INDIRECT function worked.

So solved!
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Old 07-21-2009, 05:08 PM
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Re: Selecting every nth (e.g. 10th) row for a graph

Well done.

Be aware that INDIRECT is a volatile function, so it recalculates every time anything changes. So is OFFSET, which is another alternative.

A better choice would be a solution that used INDEX.
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