How to extract specific row data from a big matrix?

Here are my data [1 5; 1 1; 1 2; 1 3; 1 1; 2 2; 2 2; 2 1; 2 3; 2 1] . Now, I want to extract the rows which have either 1 1, 1 2 , 2 1, or 2 2 and export it as a new data file. Any pointers on how to achieve this? I am able to extract by just one row value. For example, with the below code I get all the data that has 2 in the column 1. However, I do not know how to include both columns for all the above-mentioned cases i.e. 1 1, 1 2, 2 1, 2 2.

Code: data=[1 5; 1 1; 1 2; 1 3; 1 1; 2 2; 2 2; 2 1; 2 3; 2 1]; temp=data(data(:,1)==2,:);

Output: temp =

     2     2
     2     2
     2     1
     2     3
     2     1

Answer 1

[Star Strider]

Try this:

data = [1 5; 1 1; 1 2; 1 3; 1 1; 2 2; 2 2; 2 1; 2 3; 2 1];
ptrn = [1 1; 1 2; 2 1; 2 2];                                        % Patterns Matrix
Lidx = ismember(data, ptrn, 'rows');                                % Logical Index Vector For Rows
Out = data(Lidx,:)

Out =
     1     1
     1     2
     1     1
     2     2
     2     2
     2     1
     2     1

Experiment with the ismember (link) function.

[Aks]

Works like a charm! Thanks

[Star Strider]

As always, my pleasure!