As an example of file I/O, we will create an identity matrix and store its contents in a file. Perform the following steps to do so:
The identity matrix is a square matrix with ones on the main diagonal and zeroes for the rest. The identity matrix can be created with the
eyefunction. The only argument we need to give theeyefunction is the number of ones. So, for instance, for a 2 x 2 matrix, write the following code:i2 = np.eye(2) print i2 The output is: [[ 1. 0.] [ 0. 1.]]
Save the data using the
savetxtfunction. We obviously need to 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. You can check for yourself whether the contents are as expected. The code for this example can be downloaded from the book support website http://www.packtpub.com/support (see save.py).
import numpy as np i2 = np.eye(2) print i2 np.savetxt...