How can I do one-hot encoding in MATLAB?

I would like to perform one-hot encoding on the vector [1 7 10 9 8 6]' with 10 classes (numbers 1 to 10). The resulting 6x10 matrix should have a 1x10 vector in place of each number, with "1" at the position corresponding to the number and "0" at all other positions.

Answer 1

[MathWorks Support Team]

This can be done by using a logical operator '==' as follows:

>> vec = [1 7 10 9 8 6]'; % Create the vector>> A = (vec==1:10) % Find the column that corresponds to each vector entry

A = 6×10 logical array
  1  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  1  0  0  0  0  0  0  0  0  0  0  0  0  1  0  0  0  0  0  0  0  0  1  0  0  0  0  0  0  0  0  1  0  0  0  0  0  0  0  1  0  0  0  0

You can learn more about the operator here:

https://www.mathworks.com/help/matlab/ref/double.eq.html

Answer 2

[Jon Cherrie]

The function onhotencode will do this for you, e.g.,

x = [1 7 10 9 8 6]' ;
classes = 1:10;
y = onehotencode(x,2,"double",ClassNames=classes)

For more info on this function, see https://www.mathworks.com/help/deeplearning/ref/onehotencode.html

You can use onehotdecode for the reverse operation, which will also work on probability vectors, not just vectors of 1s and 0s