1. Introduction
In this example we will show the method to create a matrix and implement basic matrix manipulation in Python.
2. Create A Matrix
We can create a multi-dimensional array, which can also be viewed as a matrix.:
import numpy as np
# Create 1*3 dimensional matrix
a = np.array([1, 2, 3], dtype=int)
print(a)
# Print dimension information
print(a.shape)
print(a.size)
print(a.itemsize)
# Create 2*3 dimensional matrix
b=np.array([[1,2,3],[4,5,6]],dtype=int)
print(b)
# Dimension information
print(b.shape)
print(b.size)
print(b.itemsize)
Output:
[1 2 3]
(3,)
3
4
[[1 2 3]
[4 5 6]]
(2, 3)
6
4We can use mat() function to create a matrix.
import numpy as np
print('One matrix:')
# Create a 2*3 zero matrix
data1 = np.mat(np.zeros((3,2),dtype=int))
print(data1)
print('Another matrix:')
# Create a 2*3 integer 1 matrix. The default is floating point data. If you need an int type, you can use dtype=int.
data2=np.mat(np.ones((2,3),dtype=int))
print(data2)
Output:
One matrix:
[[0 0]
[0 0]
[0 0]]
Another matrix:
[[1 1 1]
[1 1 1]]
3. Multiply Matrix
import numpy as np
data1 = np.mat(np.ones((3,3),dtype=int))
data2=np.mat(np.ones((3,3),dtype=int))
print('Matrix multiplication:')
data3=data1*data2
print(data3)
print('Element-wise matrix multiplication')
data4=np.multiply(data1,data2)
print(data4)
Output:
Matrix multiplication:
[[3 3 3]
[3 3 3]
[3 3 3]]
Element-wise matrix multiplication
[[1 1 1]
[1 1 1]
[1 1 1]]