As an example of file I/O, we will create an identity matrix and store its contents in a file.
Note
In this and other chapters, we will use the following line by convention to import NumPy:
import numpy as np
Perform the following steps to do so:
The identity matrix is a square matrix with ones on the main diagonal and zeros for the rest (see https://www.khanacademy.org/math/precalculus/precalc-matrices/zero-identity-matrix-tutorial/v/identity-matrix).
The identity matrix can be created with the
eye()function. The only argument that we need to give theeye()function is the number of ones. So, for instance, for a two-by-two matrix, write the following code:i2 = np.eye(2) print(i2)
The output is:
[[ 1. 0.] [ 0. 1.]]
Save the data in a plain text file with the
savetxt()function. Specify the name of the file that we want to save the data in and the array containing the data itself:np.savetxt("eye.txt", i2)
A file called eye.txt should have been created...