Matrix dimensions must agree error in FOR loop

Hi all,

I am trying to do a conditional statement inside for loop, I got a very strange error of matrix dimensions must agree because I am not working with arrays at all,

the code is the following ( I am using MATLAB 2016a):: ANY HELP PLEASEEEE

for seg_nu=1:input('enter segment numbers: ')
        z=input('Is segment parallel to the y axis y/n','s')

    
    if z=='n';
        z=1
        
    elseif z=='y';
        z=2
    else
        z=3
    end 
end 

[James Tursa]

Please post the entire error message, along with a sample run that produced it. What line is producing the error?

[Ali Tawfik]

clear all
close all
clc
for seg_nu=1:input('enter segment numbers: ')
        z=input('Is segment parallel to the y axis y/n','s')
    
    if z=='no';
        z=1
        
    elseif z=='yes';
        z=2
    else
        z=3
    end 
end 

[Ali Tawfik]

line 7

Error using ==

Matrix dimensions must agree.

Error in segment_trial (line 7)

if z=='no';

Answer 1

[James Tursa]

This comparison:

z == 'no'

compares z to a 1x2 array.

And this comparison

z == 'yes'

compares z to a 1x3 array.

So you are in fact dealing with arrays here. Suppose you had entered 'yes' as the input, then guess what happens:

>> 'yes' == 'no'
Error using  == 
Matrix dimensions must agree. 

You get an error because you are comparing a 1x3 array to a 1x2 array. To make string comparisons, use string compare functions designed for it. E.g., strcmpi

if strcmpi(z,'no') || strcmpi(z,'n')
    etc.