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[Solved] How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 7:01 pm
by withnail
Hi,
I have a column with thousands of positive and negative numbers like in this example:

110.9
-100
-100
129.9
155.8
-100
120
-100
110
116
-100
117
-100
113.1
-100

I want to be able count how often and for how long the alternating pattern of positive and negative numbers occurs like so + - + - + - + - etc,, so ----- and +++++ can be ignored.
Any idea's? :-)

Re: How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 7:43 pm
by John_Ha
Add a column alongside. In it, if the number in the first column alternates with the one above, set the cell to 1. If not set it to 0. Use another column to count continuous sequences.

You get the idea ...

Re: How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 7:50 pm
by withnail
I get the idea of just scrolling down and searching for the alternating numbers in the helper column, that would be do-able.
But do you mean just set the positive numbers to 0 and the negative's to 1? Or is their a formula which specifically finds an alternation?

Re: How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 7:58 pm
by John_Ha
Code: Select all   Expand viewCollapse view
Numbers  Helper_1  helper_2
110.9      -          -
-100       1
-100       0
-123.4     1
155.8      1
-100       0
110.9      0
-100       1
-100       0
129.9      1
155.8      0

Use helper column 2 to process helper column 1, and so on, or something similar.

Re: How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 8:15 pm
by withnail
Thanks!
I understand what you mean, the second column hadn't occured to me but would help greatly.
Only thing I still don't know how to do is generate the results for the first helper....I mean, your example shows a 1 after the first -100 and then a 0 after the second -100. How do you get it to do that?!

Re: How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 8:31 pm
by John_Ha
Something like this - dinner presses so no more time. You need to think of how to handle the first and last numbers as well.

Clipboard01.gif

 Edit: Edited to correct image and file 

Re: How to find alternating numbers in a column

PostPosted: Wed Feb 20, 2019 9:43 pm
by withnail
Great John, thanks.
Enjoy your dinner! :-)