The matrix()
method is used to create a matrix from a 2-D array-like object.
Example
import numpy as np
# create 2-D array
array1 = [[1, 2], [3, 4]]
# use of matrix() to create matrix
result = np.matrix(array1)
print(result)
'''
Output:
[[1 2]
[3 4]]
'''
matrix() Syntax
The syntax of matrix()
is:
numpy.matrix(data, dtype=None, copy=True)
matrix() Arguments
The matrix()
method takes the following arguments:
data
- input data used to create the matrixdtype
(optional) - data type of the matrixcopy
(optional) - determines whether a copy ofdata
should be made or not
matrix() Return Value
The matrix()
method returns a matrix object from an array-like object.
Example 1: Create a Matrix
import numpy as np
# create a list
array1 = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
# use matrix() to create a matrix
result = np.matrix(array1, dtype = int)
print(result)
Output
[[1 2 3] [4 5 6] [7 8 9]]
If unspecified, the default dtype
is float
.
Example 2: Use of copy Argument in matrix()
import numpy as np
# create a 2-D array
array1 = [[1, 2], [3, 4]]
# create matrix with default copy=True
matrix1 = np.matrix(array1)
# modify the original data
array1[0][0] = 5
# create matrix with copy=False
matrix2 = np.matrix(array1, copy=False)
print("Matrix with copy=True:")
print(matrix1)
print("Matrix with copy=False:")
print(matrix2)
Output
Matrix with copy=True: [[1 2] [3 4]] Matrix with copy=False: [[5 2] [3 4]]
In the above example, when creating matrices using matrix()
with copy=True
, a copy of the data is made, resulting in a separate matrix.
With copy=False
, the matrix shares the data with the original object. Modifying the original data affects the matrix.