NumPy: Save two given arrays into a single file in compressed format and load it
Save Array and Load from Binary File
Write a NumPy program to save two given arrays into a single file in compressed format (.npz format) and load it.
This problem involves writing a NumPy program to save two given arrays into a single file in compressed format (.npz) and then load them. The task requires using NumPy's "savez_compressed()" function to efficiently store the arrays in a compressed file, which conserves storage space. The program then utilizes the "load()" function to retrieve the arrays from the compressed file, demonstrating how to manage and access compressed array data effectively.
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 'x' containing integers from 0 to 9 using np.arange()
x = np.arange(10)
# Creating a NumPy array 'y' containing integers from 11 to 19 using np.arange()
y = np.arange(11, 20)
# Printing a message indicating the original arrays 'x' and 'y'
print("Original arrays:")
print(x)
print(y)
# Saving the arrays 'x' and 'y' into a '.npz' file named 'temp_arra.npz' using np.savez()
np.savez('temp_arra.npz', x=x, y=y)
# Printing a message indicating loading arrays from the 'temp_arra.npz' file
print("Load arrays from the 'temp_arra.npz' file:")
# Loading data from 'temp_arra.npz' into variables 'x2' and 'y2' using np.load()
with np.load('temp_arra.npz') as data:
x2 = data['x']
y2 = data['y']
# Printing the loaded arrays 'x2' and 'y2'
print(x2)
print(y2)
Output:
Original arrays: [0 1 2 3 4 5 6 7 8 9] [11 12 13 14 15 16 17 18 19] Load arrays from the 'temp_arra.npz' file: [0 1 2 3 4 5 6 7 8 9] [11 12 13 14 15 16 17 18 19]
Explanation:
In the above exercise -
np.arange(10) creates a 1D array and stores in the variable 'x' with elements ranging from 0 to 9.
y = np.arange(11, 20): creates a 1D array and stores in 'y' with elements ranging from 11 to 19.
np.savez('temp_arra.npz', x=x, y=y): This line saves the NumPy arrays 'x' and 'y' to a compressed binary file named 'temp_arra.npz' using NumPy's native file format. The arrays are given the names 'x' and 'y' in the file.
with np.load('temp_arra.npz') as data:: This line opens the file 'temp_arra.npz' in read mode and loads its contents into a dictionary-like object called 'data'.
x2 = data['x']: This line extracts the 'x' array from the 'data' object and assigns it to the variable 'x2'.
y2 = data['y']: This line extracts the 'y' array from the 'data' object and assigns it to the variable 'y2'.
Finally print(x2) and print(y2) prints the loaded 'x2' array and 'y2' array.
Python-Numpy Code Editor: