How do I find the length (or dimensions, size) of a numpy matrix in python? -

How do I find the length (or dimensions, size) of a numpy matrix in python? -

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numpy array dimensions 2 answers

for numpy matrix in python

from numpy import matrix = matrix([[1,2],[3,4]])

how can find length of row (or column) of matrix? equivalently, how can know number of rows or columns?

so far, solution i've found is:

len(a) len(a[:,1]) len(a[1,:])

which returns 2, 2, , 1, respectively. i've gathered len() homecoming number of rows, can transpose, len(a.t), number of columns. however, feels unsatisfying , arbitrary, when reading line len(a), isn't obvious should homecoming number of rows. works differently len([1,2]) 2d python array, homecoming 2.

so, there more intuitive way find size of matrix, or best have?

shape property of both numpy ndarray's , matrices.

a.shape

will homecoming tuple (m, n), m number of rows, , n number of columns.

in fact, numpy matrix object built on top of ndarray object, 1 of numpy's 2 fundamental objects (along universal function object), inherits ndarray

python matrix numpy