How to make Matlab give different answers for different text inputs of different lengths

1 view (last 30 days)
Noah Cross on 16 Aug 2023
Commented: Noah Cross on 16 Aug 2023
A = input('Ask me anything: ','s');
if A==('Are you sentient?')
disp('Yes')
else
end
This only works if I ask "Are you sentient?", or input a sentence of equal length. So if I input "abc def ghijklmno" It'll take it and give the else answer, but if I simply ask it "Yes?" it gives me the error, "Arrays have incompatible sizes for this operation" What am I doing wrong?

Stephen23 on 16 Aug 2023
Edited: Stephen23 on 16 Aug 2023
"What am I doing wrong?"
You are using EQ (i.e. ==) for character arrays, which performs a character-by-character comparison (exactly like using EQ on numeric arrays). If you want to compare the entire text use STRCMP, STRCMPI, or similar:
if strcmpi(A,'Are you sentient?')
Stephen23 on 16 Aug 2023
Edited: Stephen23 on 16 Aug 2023
Note how EQ works for character arrays:
'cat' == 'hat'
ans = 1×3 logical array
0 1 1
which is just like EQ for numeric arrays:
[1,2,3] == [0,2,3]
ans = 1×3 logical array
0 1 1
This operation only works if the array sizes are compatible:
(which yours are not, as you noted yourself)
Noah Cross on 16 Aug 2023
Nice, that makes sense. Thanks for the answer.

DGM on 16 Aug 2023
Edited: DGM on 16 Aug 2023
I figured that for multiple cases, it would be neater to use a switch-case.
A = input('How do you eat your oatmeal?: ','s');
switch lower(A)
case 'hot'
disp('Wow! Me too! We have so much in common.')
case 'cold'
disp('That''s kind of gross.')
case {'with my mouth','with a spoon'} % you can use grouped cases
disp('Ha ha, mister funny man.')
otherwise
disp('I didn''t expect you to say that')
end
Noah Cross on 16 Aug 2023
See that's what I was actually trying to remember. Thank you.

Chunru on 16 Aug 2023
A = input('Ask me anything: ','s');
if strcmpi(A, 'Yes') % compare string (case insensitive)
disp('Yes')
else
end
Noah Cross on 16 Aug 2023
Works perfectly. Thanks

Categories

Find more on Characters and Strings in Help Center and File Exchange

R2022a

Community Treasure Hunt

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

Start Hunting!