MATLAB: Find char indices (row,column)

find

Grettings,

I have this html text file which I convert into a character array (38×343 char) using 'char' and I am triying to find the indices of all the lines starting with '<B>' using the command 'find'

So far I have typed this code,

 [row,col]=find(strncmpi('outchar', '<B>', 3)) % outchar = variable of char        array

but I keep getting empty brackets:

 row =
     []
 col =
     []

One line of the text file looks like this:

 <B><FONT SIZE=+1 COLOR="#483D8B">COASTAL WATERS FORECAST

And I want MATLAB to output

row [3 4 5 6 …] col [1:3 ….] % 1:3 = columns from 1 to 3

What can I type?

Best Answer

Variables are not enclosed in quotes:

[row,col] = find(strncmpi(outchar, '<B>', 3))

In opposite to this strncmpi('outchar', '<B>', 3) searches in the string 'outchar', which does not start with '<B>'.

I assume a cell string would be more convenient and efficient than a CHAR matrix.

STRNCMPI replies a logical vector: TRUE if the string matchs, FALSE otherwise. Therefore FIND will give you the wanted row indices, but not the columns "[1:3, ...]".

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MATLAB: Create new column in cell array based on string values in other columns

Use strjoin to merge the strings and a loop to go over the rows:

C = {'aaa', 'b', 'cccc';
     'string1', 'string2', 'string3'}
newcol = size(C, 2) + 1;
for row = 1 : size(C, 1)
   C{newcol, 4} = strjoin(C(row, :), '_');
end

Or using cellfun instead of a loop:

newC = cellfun(@(row) [row, strjoin(row, '_')], num2cell(C, 2), 'UniformOutput', false)
newC = vertcat(newC{:})

MATLAB: I have a 48483 matrix , i want to convert it to 48*48 matrix where each element of the matrix will show a list of 3 characters in a cell. how to do it

For all the numbers, you can try this:

[rows, columns, numSlices] = size(m);
index = 1;
ca = cell(1, rows*columns); % Preallocate
for row = 1 : rows
    for col = 1 : columns
        ca{index} = m(row, col, :);
        index = index + 1;
    end
end

Best Answer

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Related Question

MATLAB: I have a 48483 matrix , i want to convert it to 48*48 matrix where each element of the matrix will show a list of 3 characters in a cell. how to do it