In this article, we will discuss how to get the number of dimensions of a matrix using NumPy. It can be found using the ndim parameter of the ndarray() method.
Syntax: no_of_dimensions = numpy.ndarray.ndim
Approach:
- Create an n-dimensional matrix using the NumPy package.
- Use ndim attribute available with the NumPy array as numpy_array_name.ndim to get the number of dimensions.
- Alternatively, we can use the shape attribute to get the size of each dimension and then use len() function for the number of dimensions.
- Use numpy.array() function to convert a list to a NumPy array and use one of the above two ways to get the number of dimensions.
Get the Number of 1-Dimensions of a Matrix
Creating a 1D array using np.arrange and printing the dimension of an array.
Python3
import numpy as np# create numpy arrays# 1-d numpy array_1darr = np.arange(4) print(_1darr)# printing the 1-dimensions numpy arrayprint("Dimensions in _1darr are: ", _1darr.ndim) |
Output:
[0 1 2 3] Dimensions in _1darr are: 1v
Get the Number of 2-Dimensions of a Matrix
Creating a 2D array using np.arrange and printing the dimension of an array.
Python3
import numpy as npx = np.arange(12).reshape((3, 4))print("Matrix: \n", x) print("Dim: ", x.ndim) |
Output:
Matrix: [[ 0 1 2 3] [ 4 5 6 7] [ 8 9 10 11]] Dim: 2
Get the Number of 3-Dimensions of a Matrix
Creating a 3D array using np.arrange and np.reshape. After that, we are printing the dimension of an array using shape and len().
Python3
import numpy as np# 3-d numpy array_3darr = np.arange(18).reshape((3, 2, 3)) # printing the dimensions of each numpy arrayprint("Dimensions in _3darr are: ", _3darr.ndim)print(_3darr)# numpy_arr.shape is the number of elements in# each dimension numpy_arr.shape returns a tuple# len() of the returned tuple is also gives number# of dimensionsprint("Dimensions in _3darr are: ", len(_3darr.shape)) |
Output:
Dimensions in _3darr are: 3 [[[ 0 1 2] [ 3 4 5]] [[ 6 7 8] [ 9 10 11]] [[12 13 14] [15 16 17]]] Dimensions in _3darr are: 3
Convert a list to a Numpy Array and Get a Dimensions of a Matrix
Creating a list of 1D and 2D, using np.arrange we are converting it into a np.array and printing the dimension of an array.
Python3
import numpy as np# Use numpy.array() function to convert a list to# numpy array__1darr = np.array([5, 4, 1, 3, 2])__2darr = np.array([[5, 4],[1,2], [4,5]])print("Dimensions in __1darr are: ", __1darr.ndim)print("Dimensions in __2darr are: ", __2darr.ndim) |
Output:
Dimensions in __1darr are: 1 Dimensions in __2darr are: 2
