How to get the number of dimensions of a matrix using NumPy in Python?
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 numpy package.
- Use ndim attribute available with numpy array as numpy_array_name.ndim to get the number of dimensions.
- Alternatively, we can use 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 numpy array and use one of the above two ways to get the number of dimensions.
Example 1:
Python3
import numpy as np x = np.arange( 12 ).reshape(( 3 , 4 )) print (x.ndim) |
Output:
2
Example 2:
Python3
import numpy as np # create numpy arrays # 1-d numpy array _1darr = np.arange( 4 ) # 2-d numpy array _2darr = np.arange( 15 ).reshape(( 5 , 3 )) # 3-d numpy array _3darr = np.arange( 18 ).reshape(( 3 , 2 , 3 )) # printing the type of value obtained using # attribute 'ndim' print ( "Type of value obtained: " , type (_1darr.ndim)) # printing the dimensions of each numpy array print ( "Dimensions in _1darr are: " , _1darr.ndim) print ( "Dimensions in _2darr are: " , _2darr.ndim) print ( "Dimensions in _3darr are: " , _3darr.ndim) # 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 dimensions print ( "Dimensions in _3darr are: " , len (_3darr.shape)) # 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:
Type of value obtained: <class 'int'> Dimensions in _1darr are: 1 Dimensions in _2darr are: 2 Dimensions in _3darr are: 3 Dimensions in _3darr are: 3 Dimensions in __1darr are: 1 Dimensions in __2darr are: 2