Organising data from a matrix

Just wondering if you know how I can get the following matrix:

1.0000 0.8147

2.0000 0.3333

3.0000 0.3322

4.0000 0.1000

1.0000 0.9058

2.0000 0.2222

3.0000 0.3322

4.0000 0.2000

1.0000 0.1270

2.0000 0.1223

3.0000 0.2333

4.0000 0.1000

1.0000 0.9134

2.0000 0.1270

3.0000 1.0000

4.0000 0.1000

1.0000 0.6324

2.0000 0.8899

3.0000 0.0001

4.0000 0.1000

1.0000 0.9870

2.0000 0.5670

3.0000 0.3450

4.0000 0.2000

1.0000 0.8999

2.0000 0.9990

3.0000 0.1235

4.0000 0.4000

1.0000 0.9990

2.0000 0.9990

3.0000 0.9990

4.0000 0.0500

1.0000 0.8147

2.0000 0.3333

3.0000 0.3322

4.0000 0.1000

into a new matrix that takes the left hand column as the indices for the data from the right hand column? ie. I'm trying to get the user to specify the variable they wish to use, so when the user input is say 4, it returns a matrix with all the values in the right hand column that have a 4 next to it in the left hand one.

I had tried using regexp but this only seems to work with characters and not numbers...

Thanks! :)

Answer 1

[Guillaume]

selectedvalue = 4;
filteredmatrix = yourmatrix(yourmatrix(:, 1) == selectedvalue, :)

[Sophie Chumas]

Hi!

Thank you!

This works as it returns the 4, but doesnt return the associated values...Am I typing it out wrong?

u_s_v = input('Select the variable you wish to use by typing the number of its position in the list of variables.');
    chosen_variable = data_matrix(data_matrix(:, 1) == u_s_v);
    disp(chosen_variable);

[Torsten]

You forgot

, :

behind u_s_v.

[Sophie Chumas]

Done it!

u_s_v = input('Select the variable you wish to use by typing the number of its position in the list of variables.');
    chosen_variable = data_matrix((data_matrix(:, 1) == u_s_v), 2);
    disp(chosen_variable);

Thank you!!!!! :D

[Sophie Chumas]

I thought the , :) was a smiley face! Sorry!!! Thanks for pointing it out. Should've figured people don't use smiley faces during coding...:')