Perform operation on character arrays

11 views (last 30 days)
MarshallSc on 12 Jul 2021
Commented: MarshallSc on 16 Jul 2021
How can I perform some operations on character cells? For example, after an if statement for a numeric cell array, I get another cell array that has characters instead of numeric values, for instance:
A{1,1}=[a,b,c;a,b,c;a,b,c]
A{1,1} corresponds to a cell array that has numerical values and I want to perform some operations for only the components of the numeric cell array that has "b"s not "a"s and "c"s in the character array.
For example, the original A{1,1} is:
A{1,1}=[1,2,3;4,5,6;7,8,9]
So I want to do some calculations for (2,5 and 8) only. My original cell array in large and I cannot select the positions of all "b"s individually and have to select them in a for loop automatically, so my question is how can I identify the index of these components and performsome some operation on them? Is this even possible?
Christopher McCausland on 15 Jul 2021
No problem Marshall,
Sorry I didn't have more time to provide a fuller answer though I see Walter has it covered very well! 'find' and 'ismember' are great for char and table manipulation and can be really powerful in these kind of situations.
Christopher

Walter Roberson on 12 Jul 2021
Example
C = {'a','b','c';'a','b','c';'a','b','c'}
C = 3×3 cell array
{'a'} {'b'} {'c'} {'a'} {'b'} {'c'} {'a'} {'b'} {'c'}
A{1,1} = [1,2,3;4,5,6;7,8,9];
A{1,2} = randi(9, 3, 3);
A{1,3} = randi(9, 3, 3);
celldisp(A)
A{1} = 1 2 3 4 5 6 7 8 9 A{2} = 8 4 8 2 2 4 1 7 9 A{3} = 1 8 3 9 8 1 2 3 3
0 1 0 0 1 0 0 1 0
%maybe you want to select only those values into separate arrays
selected_values = cellfun(@(c) c(mask), A, 'uniform', 0)
selected_values = 1×3 cell array
{3×1 double} {3×1 double} {3×1 double}
%maybe you want to sum the corresponding selected values
selected_sum = sum(cell2mat(selected_values),2)
selected_sum = 3×1
14 15 18
%maybe you want to multiply the selected values by something, leaving the
%rest untouched
times_N = randi(9)
times_N = 6
selected_multiplied = 1×3 cell array
{3×3 double} {3×3 double} {3×3 double}
celldisp(selected_multiplied)
selected_multiplied{1} = 1 12 3 4 30 6 7 48 9 selected_multiplied{2} = 8 24 8 2 12 4 1 42 9 selected_multiplied{3} = 1 48 3 9 48 1 2 18 3
MarshallSc on 16 Jul 2021
Thanks Walter!
On a different note, I don't know if it's allowed to say it here, but I just wanted to thank you Walter for all of your kind and invaluable helps with the codes. You personally hepled me out a lot so I wanted to show you my deepes gratitude; your kindness and the time you put into helping others don't go unnoticed man! Thank you!

Categories

Find more on Matrix Indexing in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by