How to Group strings?

Hi Everyone,

How can I group strings based on their values?

Example: a=[1 2 3 4]; b=[0 5 3 5]; c=[9 4 7 7]; d=[9 7 3 1];

I want to make a group of the strings that have value of 3 in their 3rd column. Those will be a,b and d.

Can 1 string perticipate in more than one groups? For example Group 1 is the already mentioned one, and Group 2 would be made of the strings that have value of 9 in the 1st column. Those will be strings c and d.

Cheers, Vihar

[Jan]

"String" means a [1 x N] vector of type char in Matlab. Using the correct terms is essential when discussing about a programming language.

Answer 1

[Jan]

Storing the data in different variables is not efficient. This would be much faster and easier to expand:

Data = [1 2 3 4; ...
        0 5 3 5; ...
        9 4 7 7; ...
        9 7 3 1];
Group{1} = find(Data(:, 3) == 3);
Group{2} = find(Data(:, 1) == 9);

And even the outputs should not be numbered, but collected in a cell array.

Answer 2

[Yao Li]

a(1,1:4)=[1 2 3 4]; 
a(2,1:4)=[0 5 3 5]; 
a(3,1:4)=[9 4 7 7]; 
a(4,1:4)=[9 7 3 1];
j=1;
k=1;
for i=1:4

if((find(a(i,1:4)==3)==3)+(find(a(i,1:4)==9)==1)==2)
    group_1(j,1:4)=a(i,1:4);
    j=j+1;
    group_2(k,1:4)=a(i,1:4);
    k=k+1;
else
    if(find(a(i,1:4)==3)==3)
    group_1(j,1:4)=a(i,1:4);
    j=j+1;
    elseif(find(a(i,1:4)==9)==1)
    group_2(k,1:4)=a(i,1:4);
    k=k+1;
    else
    end

end
end