finding the maximum within a specific range

Hello,

for the attached table we would like to find the index of the max point of the variable NE8 within the range of (200,400) applied on the variable GDALT. This might be a simpel task and I am complicating it but if anyone can help.

Answer 1

[Githin George]

Hi Salma,

My understanding is that for rows having GDALT in range 200-400 you would like to find the row where NE8 is maximum.

Please see if this code helps

txt = readtable("table.txt"); 
% I'm adding an Index Column, in case you specifically want the index
txt.INDEX = (1:height(txt))';

subTable = txt(txt.GDALT >=200 & txt.GDALT <=400, :);

% getting idx in the subtable using max function
[~,idx] = max(subTable.NE8,[],'omitnan');

% this row contains the required result. You can use the index from this
% row. 
result = subTable(idx,:)

Hope this helps.

[Salma fathi]

Thank you for the quick reply. what you have proposed is giving me the index in the table "Subtable", whereas it would be much helpful for me if I can get the index of the max point in the original table. Is that possible?

And I am getting this error for the last line

Unrecognized function or variable 'mat'.

Error in PeakConstruction (line 218)
 result = mat(idx,:);

[Githin George]

I've corrected the mistake in last line. The last element in result will contain the 'index' from original column.

[Salma fathi]

Thank you so much this helped me alot and solved my problem. Appreciate the help.

Answer 2

[KSSV]

T =readtable('https://in.mathworks.com/matlabcentral/answers/uploaded_files/1075965/table.txt') ;
NE8 = T.NE8 ;
idx = NE8>200 & NE8<400 ; 
val = max(NE8(idx))

val =

  0×1 empty double column vector

It looks like there is no data in the given range.