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arnair811-Visitor
1-Visitor
May 24, 2020
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program to compare 2 matrices

  • May 24, 2020
  • 3 replies
  • 5254 views

Hi, 

       I need to write a program to compare two matrices and eliminate non-identical rows. For example, please see attachment. In this case Matrix B can only contain numbers found in Matrix A. I need to compare each value of A with B and output values of B that matches with A (in the same order). Problem is some of the numbers in A do not appear in B and therefore, I am not able to use the match function. I would greatly appreciate any help.

 

Thanks.

 

 

Best answer by terryhendicott

Hi,

 

I take it back,  The data presented in the first set of data on 24/03/2020 is different in B.  On 24/03/2020 all values of A exist in B so my use of the match command works.

 

The second data set on 24/05/2020 only some values of A exist in B.  So before use of the match command each time you need to check A is in B.

Capture.JPG

You can use match safely with any number in "otherresult"

Capture2.JPG

Capture3.JPG

 

 

Regards

Terry

3 replies

T
21-Topaz II
terryhendicott21-Topaz II
21-Topaz II
May 24, 2020

Hi,

 

This exact question (including the values) has been asked before.

 

Here is the solution given then.

 

Cheers

Terry

    W
    Werner_E25-Diamond I
    25-Diamond I
    May 24, 2020

    It looks to me that your solution is for a different problem and a different excel sheet. There is not data in the area "F3:G60" in the sheet provided by the OP.

     

    T
    21-Topaz II
    terryhendicott21-Topaz II
    21-Topaz II
    May 24, 2020

    Hi,

    It looks to me that your solution is for a different problem and a different excel sheet. There is not data in the area "F3:G60" in the sheet provided by the OP.

     

    This post is a subset of data in a question posted earlier.  In the earlier post the data in area B2:B18 is a calibration factor.  In the earlier post data in area G3:G60 is an experimental result.  The problem is to use the right calibration factor from B3:B18 on the data in G3:G60 depending on the matching numbers in A3:A18 and F3:F60.

     

    It is clearly a homework question where the second submitter has reduced the data set.

     

    I enclose the first submitter's dataset.and the full answer to the homework in question.

    W
    Werner_E25-Diamond I
    25-Diamond I
    May 24, 2020

    You could create a custom "match" function which returns whatever value (maybe NaN or 0) you want in case the built.in "match" command fails.

     

    I am irritated by you writing "in the same order". Does this mean that 60016 would be not in the result list because it appears in A BEFORE 60029 but in B just after 60029 ?
    What exact result do you expect using your test data and why do you post an excel sheet and not a simple Mathcad sheet with the two matrices already included? Would be easier to deal with.

      L
      LucMeekes23-Emerald IV
      23-Emerald IV
      May 24, 2020

      The attached worksheet does what you ask (per your description): It checks all values in B, compares them with values in A and outputs only those values of B that are also in A, in the order in which they appear in B.

      LucMeekes_0-1590324664161.png

       

      Given your data, it is now (also) checked that ALL values in B do in fact occur in A.

      Is this what you want?

      For clarity, if I add 2 to all values of B, some of those sums will not be in A, the result is a smaller list:

      LucMeekes_1-1590325026539.png

      Success!
      Luc

       

       

        T
        21-Topaz II
        terryhendicott21-Topaz IIAnswer
        21-Topaz II
        May 24, 2020

        Hi,

         

        I take it back,  The data presented in the first set of data on 24/03/2020 is different in B.  On 24/03/2020 all values of A exist in B so my use of the match command works.

         

        The second data set on 24/05/2020 only some values of A exist in B.  So before use of the match command each time you need to check A is in B.

        Capture.JPG

        You can use match safely with any number in "otherresult"

        Capture2.JPG

        Capture3.JPG

         

         

        Regards

        Terry

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