MATLAB Answers

Error when If statement is not true

5 views (last 30 days)
Hello,
I have a user supplying a 'Yes' or 'No' input to a question. I want to use the response to determine if plots are created or not. If I select 'Yes', the code runs fine. However, if I select 'No', I get this error: Error in PostProcessing_filetest (line 118) , if answer == 'Yes'. Why won't Matlab go to the else statement if the if-statement is not true? Can someone help point out my error? Below is a portion of my code. The variables in the if-portion of the code are defined before-hand. Thank you!
....
quest = 'Do you want another set of maps?';
answer = questdlg(quest);
if answer == 'Yes'
strm1a = 'What is the map height (pixels)?';
strm2a = 'What is the map width (pixels)?';
strm3a = 'What is the min Frequency?';
strm4a = 'What is the max Frequency?';
strm5a = 'What is the min x parameter?';
strm6a = 'What is the max x parameter?';
strmat = {strm1a,strm2a,strm3a,strm4a,strm5a,strm6a};
xminstrg = round(min(min(min(xparm))));
xmaxstrg = round(max(max(max(xparm))));
default = {'300','500','0','200','0','1000'};
inputmapa = inputdlg(strmat,'New Map Parameters',[1 50],default);
h = str2double(inputmapa{1});
w = str2double(inputmapa{2});
mapFmin = str2double(inputmapa{3});
mapFmax = str2double(inputmapa{4});
mapxmin = str2double(inputmapa{5});
mapxmax = str2double(inputmapa{6});
i = 1;
for i = 1: numfiles
figure(fignum)
fignum = fignum + 1;
hold on
axis([mapxmin mapxmax mapFmin mapFmax])
himage = imagesc(xparm(:,:,i),Farray,Amp(:,:,i));
colormap;
hAxes = himage.Parent;
ampmax(i) = max(max(Amp(:,:,i)));
hAxes.CLim = [s,ampmax(i)/10];
xlabel(strcat(namexparm,'(', unitsxparm, ')'));
ylabel("Frequency(Hz)");
title(strcat("Waterfall map for: Test ", testname , "-", fn(i)))
colorbar;
truesize([h w]);
hold off
end
else
disp("no more plots");
end
.....

  0 Comments

Sign in to comment.

Accepted Answer

Amy Haskins
Amy Haskins on 5 Nov 2018
The problem is with using == on character vectors. Each character is treated as a separate element and compared individually. This will error when the lengths of the strings you are trying to compare doesn't match.
>> 'no' == 'yes'
Matrix dimensions must agree.
>> 'yes' == 'yes'
ans =
1×3 logical array
1 1 1
There are 2 easy solutions. One is to use strcmp. The other is to use the string data type (introduced in R2016b) which will behave more like you were expecting.
>> strcmp('no','yes')
ans =
logical
0
>> "no" == "yes" % String scalars
ans =
logical
0

  1 Comment

Kateri Kaminski
Kateri Kaminski on 5 Nov 2018
Oh this makes sense. Thanks!

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!