1
\$\begingroup\$

I need a NumPy matrix with comparisons among all elements in a sequence:

from numpy import matrix
seq = [0, 1, 2, 3]
matrix([[cmp(a, b) for a in seq] for b in seq])

I'd like to know if there is a better way to do this.

\$\endgroup\$
5
\$\begingroup\$

Why are you using matrix rather than array? I recommend sticking with array

As for a better way:

seq = numpy.array([0, 1, 2, 3])
numpy.clip(seq[:,None] - seq, -1, 1)
  1. seq[:, None], moves the numbers into the second dimension of the array
  2. seq[:, None] - seq broadcasts the numbers against each other, and subtracts them.
  3. numpy.clip converts lower/higher values into 1 and -1
\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.