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

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:

X1 = xlsread('Abb73at100.xlsx','A1:A63');

Y1 = xlsread('Abb73at100.xlsx','B1:B63');

V = 40.020;

A1 = pi*(X1).^2;

Int1 = trapz(A1, Y1);

X2 = xlsread('Abb73at100.xlsx','A64:A130');

Y2 = xlsread('Abb73at100.xlsx','B64:B130');

A2 = pi*(X2).^2;

Int2 = trapz(A2, Y2);

Answer 1

[Chetan Bhavsar]

[num data raw] = xlsread('Abb73at100.xlsx');
% 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

[Vishnuvardhan Naidu Tanga]

Hello @Chetan Bhavsar

Thank you.

[Chetan Bhavsar]

Hello @Vishnuvardhan Naidu Tanga

Please take look at where 0 should be incuded.

in above code i have added it as positive number.

[Vishnuvardhan Naidu Tanga]

Thats fine. I am considering the zero as a positive integer. Thanks once again

Answer 2

[Mathieu NOE]

Hello

try this - it also only need one call to readxls

data = xlsread('Abb73at100.xlsx');
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)