Matrix Manipulation code help

I have a training label for 3 different classes in a matrix of size 1*178 example t=[1 1 1 3 1 2 3 1 ... .....]. Anyone please help me to write an efficient code for generating a new matrix of size 3*178 where based on the value in "t", the corresponding location in columns should be 1.

for the above example. the output will be like the following matrix:

[1 1 1 0 1 0 0 1.... 0 0 0 0 0 1 0 0..... 0 0 0 1 0 0 1 0.....]

Answer 1

[Walter Roberson]

[t(:) == 1,  t(:) == 2, t(:) == 3]

Answer 2

[Stephen23]

For a simple generalized solution use bsxfun:

>> t = [1 1 1 3 1 2 3 1]
>> bsxfun(@eq,(1:3).',t)
ans =
   1   1   1   0   1   0   0   1
   0   0   0   0   0   1   0   0
   0   0   0   1   0   0   1   0