MATLAB: Access subset of elements in a cell

cell arraysMATLABmatrix manipulation

I have created the following cell C from reading a txt file. 
{["0719-3"    ]}    {["0729-2"    ]}    {["0742-5"    ]}    {["0742-6"    ]}    {["0744-5"     ]}    {["0744-6"     ]}
{84444×4 double}    {84444×4 double}    {84444×4 double}    {84444×4 double}    {84444×4 double}     {84444×4 double}
I want to switch the sign of the 2nd to 4th colums of each matrix (second row). Is there any way I can access all the submatrix (:,2:4) in the cell? I habe tried C{2,:}(:,2:4) (I was hoping to do something like C{2,:}(:,2:4) = -C{2,:}(:,2:4)but it does not work.

Best Answer

When typing
C{2,:}(:,2:4)
you are probably getting the error message "Expected one output from a curly brace or dot indexing expression, but there were 6 results" which pretty much explains what is happening. Note that 
C{2,1}(:,2:4)
does not error.
You could use cellfun on C(2,:) as follows:
C =  [{"A1"},{"A2"},{"A3"}; repmat({magic(4)},1,3) ];  % sample cell array
C(2,:) = cellfun(@(x) x.*[1,-1,-1,-1], C(2,:), 'UniformOutput', false);
>> C
C =
  2×3 cell array
    {["A1"    ]}    {["A2"    ]}    {["A3"    ]}
    {4×4 double}    {4×4 double}    {4×4 double}
>> C{2,1}
ans =
    16    -2    -3   -13
     5   -11   -10    -8
     9    -7    -6   -12
     4   -14   -15    -1
Related Question