NumPy: Save a given array to a binary file

NumPy: Basic Exercise-35 with Solution

Write a NumPy program to save a given array to a binary file.

This problem involves writing a NumPy program to save a given array to a binary file. The task requires utilizing NumPy's built-in functions to efficiently store the array's data in a binary format, which allows for compact storage and quick loading. By saving the array to a binary file, the program ensures data persistence and facilitates efficient data handling for future use.

Sample Solution :

Python Code :

# Importing the NumPy library with an alias 'np'
import numpy as np

# Importing the 'os' module for operating system-dependent functionality
import os

# Creating a NumPy array 'a' with integers from 0 to 19 using np.arange()
a = np.arange(20)

# Saving the NumPy array 'a' as a file named 'temp_arra.npy' using np.save()
np.save('temp_arra.npy', a)

# Printing a message checking if the file 'temp_arra.npy' exists or not
print("Check if 'temp_arra.npy' exists or not?")

# Checking if the file 'temp_arra.npy' exists using os.path.exists()
if os.path.exists('temp_arra.npy'):
    # Loading the data from 'temp_arra.npy' into 'x2' using np.load()
    x2 = np.load('temp_arra.npy')
    
    # Checking if the loaded array 'x2' is equal to the original array 'a' using np.array_equal()
    print(np.array_equal(a, x2)) 

Output:

Check if 'temp_arra.npy' exists or not?
True                         

Explanation:

The above code creates a NumPy array, saves it to a file, loads it back into another NumPy array, and checks if the original and loaded arrays are equal.

‘a = np.arange(20)’ creates a 1D array 'a' with elements ranging from 0 to 19.

np.save('temp_arra.npy', a): This statement saves the NumPy array 'a' to a binary file named 'temp_arra.npy' using NumPy's native file format.

if os.path.exists('temp_arra.npy'):: This statement checks if the file 'temp_arra.npy' exists in the current directory using the os.path.exists() function.

x2 = np.load('temp_arra.npy'): If the file exists, this line loads the contents of 'temp_arra.npy' back into a NumPy array named 'x2'.

Finally ‘print(np.array_equal(a, x2))’ uses the np.array_equal() function to check if the original array 'a' and the loaded array 'x2' are element-wise equal. If they are equal, it prints 'True', otherwise, it prints 'False'.

Python-Numpy Code Editor:

Previous: NumPy program to add a vector to each row of a given matrix.
Next: NumPy program to save two given arrays into a single file in compressed format (.npz format) and load it.