Using logical index matrix to create another matrix with values

Hi All,

I have a matrix (E) with 180 x45 with values. I would like to create another matrix where the values are >1E9. First I found the indexes (idx) of the values that are >1E9 in matrix E. Now I would like to use that matrix index (idx) to create the another matrix (E2) that have the values that are >1E9. But it created just one column data insted not a matrix. How can I solve this?

Thank you

idx=E>1E9;

E2=E(idx);

Birsen

[Birsen Ayaz-Maierhafer]

Thank you. It worked.

Answer 1

[Steven Lord]

What do you want the elements that did not satisfy the condition in your original matrix to be in the new matrix? You can't have a "Swiss cheese" matrix (one with holes in it.)

Here's one example that fills in where those holes would have been with NaN values.

A = magic(4)

A = 4×4

16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1

ind = A > 8

ind = 4×4 logical array
   1   0   0   1
   0   1   1   0
   1   0   0   1
   0   1   1   0

B = NaN(4)

B = 4×4

NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN

B(ind) = A(ind)

B = 4×4

16 NaN NaN 13 NaN 11 10 NaN 9 NaN NaN 12 NaN 14 15 NaN

Note that if you'd tried to use ind to extract just those elements of A, you are correct that you'd receive a vector. Remember, no holes allowed.

C = A(ind)

C = 8×1

16 9 11 14 10 15 13 12