CODEWITHSUNDEEP
stringmatlabmatrix
Lincoln Lo
Lincoln Lo

Reputation: 1

Reading and detect string from a column of matrix

I have a column of strings in a matrix 

X = ['apple1 (15%)'; 'apple2 (15%)'; 'apple3 (15%)'; 'orange1 (15%)'; 'orange2 (15%)'; 'orange3 (15%)' ]

I need to create another column of matrix to redefine the content of X.

For example, I want MATLAB to redefine 'apple' as 1 and 'orange' as 2. So in the end I would expect something like this:

[1; 1; 1; 2; 2; 2]

However, the MATLAB could not read the string when I read the column of strings:

theMatrix = xlsread(myFile.xls);

for i = numTotalTrials;
 X = theMatrix(i,2)

> X = Nan

Further, I am using strfind to redefine the column:

t = strfind(X,'a');
if t == 1
    newColumn = 1
else
    newColumn = 2
end

Does MATLAB work this way? Thanks!

Upvotes: 0

Views: 101

Answers (2)

Amro
Amro

Reputation: 124563

Another solution using regular expressions:

%# note the use of cell-arrays
X = {'apple1 (15%)'; 'apple2 (15%)'; 'apple3 (15%)'; 
     'orange1 (15%)'; 'orange2 (15%)'; 'orange3 (15%)'};

%# match either apples or oranges
m = regexp(X, '^(apple|orange)', 'match', 'once');

%# which one was found
[~,loc] = ismember(m, {'apple','orange'})

The result:

>> loc
loc =
         1
         1
         1
         2
         2
         2

Upvotes: 1

Mehrwolf
Mehrwolf

Reputation: 8527

Don't know, if this is exaclty what you are looking for but starting with 

X = ['apple1 (15%)'; 'apple2 (15%)'; 'apple3 (15%)'; 
     'orange1 (15%)'; 'orange2 (15%)'; 'orange3 (15%)'];

I would define an output vector result, loop over the input and just look for the desired strings using strfind which might look like 

result = zeros(size(X, 1), 1);
for row = 1 : size(X, 1)
    if ~isempty(strfind(X(row,:), 'apple'))
        result(row) = 1;
    elseif ~isempty(strfind(X(row,:), 'orange'))
        result(row) = 2;
    end
end

This will return

result = [1; 1; 1; 2; 2; 2];

Upvotes: 0

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