# how to identify and read positive and negative data from excel?

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Vishnuvardhan Naidu Tanga on 27 Oct 2021
Answered: Mathieu NOE on 27 Oct 2021
Hello all,
I am trying to read excel data which has positive and negative. Is there any way to identify the data. I am currently using the following code to identify it. But is theree any other simple way because i need to analyse other data where the number of cells change. Thanks in advance.
My code:
V = 40.020;
A1 = pi*(X1).^2;
Int1 = trapz(A1, Y1);
A2 = pi*(X2).^2;
Int2 = trapz(A2, Y2);

C B on 27 Oct 2021
Edited: C B on 27 Oct 2021
% get data in two columns
col_1 = num(:,1);
col_2 = num(:,2);
% get negative index by col_1<0
Neg_X = col_1(col_1<0);
Neg_Y = col_2(col_1<0);
% get positive index by col_1>=0
POS_X = col_1(col_1>=0);
POS_Y = col_2(col_1>=0);
A1 = pi*(Neg_X).^2;
Int1 = trapz(A1, Neg_Y)
Int1 = 0.5773
A2 = pi*(POS_X).^2;
Int2 = trapz(A2, POS_Y)
Int2 = 0.5789
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C B on 27 Oct 2021
Please take look at where 0 should be incuded.
in above code i have added it as positive number.
Vishnuvardhan Naidu Tanga on 27 Oct 2021
Thats fine. I am considering the zero as a positive integer. Thanks once again

Mathieu NOE on 27 Oct 2021
Hello
try this - it also only need one call to readxls
X = data(:,1);
Y = data(:,2);
X1 = X(X<0);
X2 = X(X>=0);
Y1 = Y(X<0);
Y2 = Y(X>=0);
V = 40.020;
A1 = pi*(X1).^2;
Int1 = trapz(A1, Y1)
A2 = pi*(X2).^2;
Int2 = trapz(A2, Y2)