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for loop that changes specific letters to numbers

Asked by Seaturtle on 2 Oct 2019
Latest activity Commented on by Adam Danz
on 4 Oct 2019
I want to replace the vowels AEIOU with the number 0 and all other letters with the number 1. For example the output should be ans = [0 1 1 1 0] if the user inputs apple. I know I must be misunderstanding how to get the loop to go through my whole string. This is what I have managed so far.
party = input('What is your answer? ', 's');
n = length(party)
for i = 1:n
if i == 'A'
disp(0)
elseif i == 'B'
disp(1)
elseif i == 'C'
disp(1)
end
end

  0 Comments

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3 Answers

Answer by Walter Roberson
on 2 Oct 2019
 Accepted Answer

party = input('What is your answer? ', 's');
n = length(party)
for i = 1:n
if party(i) == 'A'
party(i) = 0;
elseif i == 'B'
party(i) = 1;
elseif i == 'C'
party(i) = 1;
end
end
disp( double(party) )

  7 Comments

I ended up making the changes myself with the original answer that you posted, so it worked out great. Thank you!
It would be nice if 'vowel' were a category option.
The problem with that is what is a vowel or not depends on the language. Some letters such as 'y' in english can also qualify as a vowel or consonant depending on the word.
True. It would be neat to play around with one of the vowel classification algorithms that are not specific to any language such as this one (link below) that is based on character co-occurrences. It wouldn't necessarily solve the fuzzy set problem but it would be a semi-objective, language-independent classification.

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Answer by Adam Danz
on 2 Oct 2019
Edited by Adam Danz
on 2 Oct 2019

No loop needed.
str = 'apple';
isConsonant = ~ismember(lower(str),'aeiou') %lower() makes it not case sensitive
If you really wanted to do that in a loop,
n = numel(party);
isConsonant = true(1,n);
for i = 1:n
if ismember(party(i),'aeiou')
isConsonant(i) = false;
end
end
In both cases, isConsonant is a logical vector. If you want a double vector of 0/1 instead of false/true,
isConsonant = double(isConsonant);

  8 Comments

semi-vowel does sound like the correct term.
In practice, y probably acts like a vowel more than it acts like a consontant .
Thanks for this answer! This really helped with my understanding of not using a loop to do something with shorter code.
Glad I could chip in! :)

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Answer by Jos (10584)
on 3 Oct 2019

Another option:
str = 'apple';
TF1 = any(lower(str) ~= 'aeiou'.')

  6 Comments

TF1 = all(lower(str) ~= 'aeiou'.')
Thanks for the corrections :-)
+1
This implicit expansion solution is faster and neater than my ismember() solution.

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