If statement for the structure in table

I have a table like this:

%% table info
alphabet = {'A';'A';'B';'A';'C';'D';'C'};
val = [52.1;20.0;13.27;10.49;4.35;4.16;3.78];
relation = {[2,5];[2,5];3;[10,11];2;5;9};
inx = [2;2;5;6;10;12;12];

T = table(alphabet,val,relation,inx);

I have two problems. First, want to find the rows that consist of 'A'.

find(T.alphabet{:}=='A')

Second, count the occurrences of 'A', 'B', 'C', and 'D'.

I try to use 'accumarray' but it does not work.

Answer 1

[madhan ravi]

FIND_rows_of_A = find(strcmp(T.alphabet, 'A'))
%or
FIND_rows_of_A = find(ismember(T.alphabet, 'A'))
[Alphabets, ~, c] = unique(T.alphabet);
counts = accumarray(c, 1); % use it the right way ;)
Wanted = [array2table(Alphabets), array2table(counts)]
% if you're using recent versions of MATLAB then
Wanted = groupsummary(T, 'alphabet')
%or
Wanted = groupcounts(T, 'alphabet')