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Why does Matlab give me the entire string instead of just one element?

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AelinAG
AelinAG on 6 Sep 2018
Commented: Walter Roberson on 7 Sep 2018
Hi, I'm trying to extract a value of a string, but if I type string(1) Matlab gives me the entire string.. How should I solve this?

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Answers (3)

ADragon
ADragon on 6 Sep 2018
I am guessing you might have a cell array instead of a string. What happens when you do this?
str = 'Hello Matlab';
str(1)
It should return 'H'. If you have a cell array it will return the whole string. For example:
c = {'Hello Matlab'};
c(1)
To get the first character use
c{1}(1)
which is first cell, first element of cell array c.
AD

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AelinAG
AelinAG on 6 Sep 2018
That's not allowed, it's for an assignment and we can't use num2str or str2num :(
ADragon
ADragon on 6 Sep 2018
That stinks. Your teacher must be after something very specific. I would check docs for the functions that you CAN use. I'm not sure how to do what you are asking without functions.
Walter Roberson
Walter Roberson on 7 Sep 2018
Brace indexing is not supported for variables of this type
That establishes that your input is not a cell array of character vectors, and also establishes that your input is not a string object.
If your input were a character vector then using (1) to index it would have only returned a single character instead of the whole thing.
I therefore suspect that you are not being given a cell array or a character vector or a string object. I suspect that you are being passed a numeric object. What shows up if you ask for
class(NameOfVariableGoesHere)
?

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YT
YT on 6 Sep 2018
It would be usefull if you read the documentation on strings (and maybe also char)
mystring = "HelloWorld"; %notice double quotes
mychar = 'HelloWorld'; %notice single quotes
mystring(1)
%Output: HelloWorld
mychar(1)
%Output: H
string2char = char(mystring);
string2char(1)
%Output: H
As you can see you can easily make a char array from a string like this

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YT
YT on 6 Sep 2018
string2char is just a (unfortunate) variable name to store the result of making a character array from your string (and not a build-in function). You could name it whatever, doesn't really matter.
AelinAG
AelinAG on 6 Sep 2018
Ah I understand, sorry, I'm new to programming! My string is a number that is given in the input of a function though, so how do I extract one of the elements of that number?
YT
YT on 6 Sep 2018
Something like this then
input = "987654"; %input string
temp = char(input); %temporary variabele
output = temp(1) %will output '9' of type char

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Image Analyst
Image Analyst on 7 Sep 2018
It's probably because string is a built-in function name. Use a different name for your variable. From the help for the string() function:
Description
example
str = string(A) converts the input array to a string array.
For example:
>> string(1)
ans =
"1"

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