MATLAB: How to get Y values corresponding to X from matrix B nx2 or from X and Y matrices

Question

We have the data of matrix B (201×2) which consist of x_i (1×201) and y_i (1×201) matrices.

We want program to prompt y_i value corresponding to x_i value that we will write.

I'm open for other solutions too.

(Don't mind the part before %%%% INTERP1 %%%% )

clear all;
close all;
clc;
h=openfig('Fig2m005.fig');       %%%% Load graphic
h=findobj(gca,'Type','line');    %%%% Make program read graphic
x=get(h,'Xdata');                %%%% Values
y=get(h,'Ydata');
A=[];                            %%%% Create empty matrix so you can put x and y
A(:,1)=x;                        %%%% Put x values to 1st column
A(:,2)=y;                        %%%% Put y values to 2st column
dlmwrite('m005.txt',A,',');      %%%% Write A matrix as a txt text file, value that we selected by hand 
%%%% INTERP1 %%%%
x_i = 0:0.0001:0.02;
y_i = interp1(x, y, x_i, 'linear');
B=[];                            
B(:,1)=x_i;                        
B(:,2)=y_i;  
dlmwrite('m005_interp1.txt',B,',');
figure(2)           %%%% Creates new window for new interpolated graph ( as you can see there is no difference )
plot(x_i, y_i,'g')  %%%% line names in data file 
title('Dimensionless design breaker height versus relative depth at structure') %% naming 
xlabel('ds/gT^2')
ylabel('Hb/ds')
axis ([0 0.02 0 2])

Answer 1

Problem is caused because of the decimal use and format ( I guess ).

x_input=input('Put X value to read y_i= ')
x_place=find(abs(x_i-x_input)<10^-6) %right to 10^-6
y_read=y_i(x_place)

Reference

Reference2