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LucMeekesAnswer
23-Emerald V
Jan 26, 2026 3:19 PM UTC

Match gives the location(s) (index/indices) of the element(s) found, while lookup gives the value(s) of all/an element(s) in (a) location(s) that correspond(s) to the element(s) found.

With matrix:

LucMeekes_0-1769441034898.png

LucMeekes_2-1769441058045.png

tells you that the 2 is found at row position 1 in colum 0.

LucMeekes_3-1769441095808.png

gives you the value in column 1 of that matrix, at the same row where 2 is found in the first column (column 0).

 

You can also get the value of the element found, by looking up in the same array as where you search...:

LucMeekes_4-1769441260658.png

but the usefullness of this may be questionable.

 

As Werner shows, you get multiple results, if the value you look for occurs multiple times in the array.

 

Success!

Luc

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8 replies

LucMeekes23-Emerald VAnswer
23-Emerald V
Jan 26, 2026 3:19 PM UTC

Match gives the location(s) (index/indices) of the element(s) found, while lookup gives the value(s) of all/an element(s) in (a) location(s) that correspond(s) to the element(s) found.

With matrix:

LucMeekes_0-1769441034898.png

LucMeekes_2-1769441058045.png

tells you that the 2 is found at row position 1 in colum 0.

LucMeekes_3-1769441095808.png

gives you the value in column 1 of that matrix, at the same row where 2 is found in the first column (column 0).

 

You can also get the value of the element found, by looking up in the same array as where you search...:

LucMeekes_4-1769441260658.png

but the usefullness of this may be questionable.

 

As Werner shows, you get multiple results, if the value you look for occurs multiple times in the array.

 

Success!

Luc

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    YA_1096379815-MoonstoneAuthor
    15-Moonstone
    Jan 27, 2026 8:08 AM UTC

    Thanks a lot 

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    Werner_E
    Werner_E25-Diamond I
    25-Diamond I
    Jan 26, 2026 3:20 PM UTC

    match(z,A) returns a vector of indices of the position(s) z is found in matrix A

    lookup(z,A,B) returns a vector of values from matrix B from the position(s) z is found in A

     

    See the Prime help here: Lookup Functions

     

    Simple example:

    Werner_E_0-1769441482857.png

     

    EDIT; Oh, too late—Luc has beaten me by one minute. 🙂

     

     

     

     

     

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      YA_1096379815-MoonstoneAuthor
      15-Moonstone
      Jan 28, 2026 8:53 AM UTC

      Hi Werner 

      I'm trying to use this function, that you showed me before 

      YA_10963798_0-1769589784913.png

      to get q in the corresponding ztips depth

      I wrote it like this 

      YA_10963798_1-1769590237357.png

      can you tell me what is wrong with this program 

      Should I use match or change the iterator ? 

      I attached the sheet 

      Thanks

      Yusra 

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      Werner_E
      Werner_E25-Diamond I
      25-Diamond I
      Jan 28, 2026 10:33 AM UTC

      From the picture I see that your program does some calculations but at the end it returns "q" unchanged and that's what you finally get. 😉

       

      Could it be that you are looking for something like this:

      Werner_E_2-1769596424183.png

       

      The results are all NaN's because none of the values in ztips matches any  value in the vector ztop (which is then called z in the program).

      I also suspect that you meant to use -z when you call the program and not ztop (qused := qs;d(q.-z,ztips). But this does not change the NaN's because none of the values in ztips matches any value in -z as well.
      At least i guess that the second argument when calling qs;d should be a 2312x1 vector like the three vectors in q and not a 11x1 vector like ztop .

      Werner_E_1-1769596371153.png

       

      I can't remember what the question was when I provided the function you refer to and what the data was at that time.and I don't know what you intend to calculate now. Maybe you need to use a modifier like "geq", "lt", "near", etc. (see the help), but I can't possibly know.

       

       

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