Search for individual characters within string

Say I have:

cell_array={'AX','BY'};

It is easy to manipulate the terms 'AX' and 'BY' (to isolate, sort, identify etc.), but I cannot seem to find an approach to search for the individual components within 'AX' or 'BY'.

I would like to consider each character in the string individually, i.e. 'A' or 'X' in 'AX'. Basically, I want to be able to search for 'A' or 'X' in 'AX' without having to modify 'AX'.

Is that possible?

Answer 1

[per isakson]

Run this

cell_array = {'AX'; 'BY'; 'CXXYXXYYYX'; 'DYXZZZXXYXZ'};
cac = cellfun( @(c) strfind( cell_array, c ), {'A','Y'}, 'uni', false );
cac{2}
cac{2}{3}

ans = 
    []
    [         2]
    [1x4 double]
    [1x2 double]
ans =
     4     7     8     9
>>

Which says that the letter, "Y", exists in the second, third and forth string. In the third string "Y" appears in position 4,7,8 and 9.

Answer 2

[Image Analyst]

Try to adapt this demo code:

% Construct a sample cell array.
cell_array={'AX'; 'BY'; 'CXXYXXYYYX'; 'DYXZZZXXYXZ'};
% Now find X and Y locations for each row.
for k = 1 : size(cell_array, 1)
  % For each row in the cell array...
  % Get the string inside the cell.
  cellContents = cell_array{k}
  % Find arrays giving the indexes of X and Y.
  xIndexes = strfind(cellContents, 'X')
  yIndexes = strfind(cellContents, 'Y')
end

Answer 3

[Rui Zhao]

For searching for 'x' in 'AX', you can search the uppercase of input via doing this:

char(double('x') - 32); % translate the 'x' into ASCII number and subtract 32 to get uppercase 'X'.

For searching lowercase, vice versa. char(double('X') + 32);

[Ole Hansen]

Thanks for your comment. It is not, however, an issue about lower and upper case. It is about searching for individual characters within a string, and about the position of the first and second character (the individual terms are always of length 2).

[Image Analyst]

Isn't the position of the first character always 1 and the position of the second character always 2?