Question

I am looking for a way to remove the NaN numbers from a matrix in MATLAB efficiently (i.e. without using a for loop)

I will provide a quick example to illustrate what I am trying to achieve:

Say I have a matrix M:

          3.00          1.00
          1.00          3.00
           NaN           NaN
          3.00          3.00
          1.00          1.00
           NaN           NaN
           NaN           NaN
           NaN           NaN
           NaN           NaN
           NaN           NaN

I would like to find a way to change this to

          3.00          1.00
          1.00          3.00
          3.00          3.00
          1.00          1.00

I am currently trying to do this via M(isfinite(M)) but that ends up returning a vector instead of the matrix. Is there a trick to have it return a matrix instead?

Answer 1

If you have either no NaNs or all NaNs on each row, you can do the removal using:

M(isfinite(M(:, 1)), :)