NumPy: Save a NumPy array to a text file

Last update on March 24 2025 13:39:48 (UTC/GMT +8 hours)

Save Array to Text File

Write a NumPy program to save a NumPy array to a text file.

Sample Solution:

Python Code:

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

# Generating an array using arange() from 1.0 to less than 2.0 with step 36.2
a = np.arange(1.0, 2.0, 36.2)

# Saving the array 'a' into a file named 'file.out' with ',' as a delimiter using savetxt()
np.savetxt('file.out', a, delimiter=',')

Explanation:

In the above code –

a = np.arange(1.0, 2.0, 36.2): This line creates a NumPy array ‘a’ using the np.arange() function with a start value of 1.0, an end value of 2.0, and a step size of 36.2. However, since the end value (2.0) is smaller than the start value plus the step size (1.0 + 36.2), the resulting array will only contain the start value: [1.0].

np.savetxt('file.out', a, delimiter=','): This line saves the NumPy array ‘a’ to a file named 'file.out' using a comma delimiter. In this case, the content of 'file.out' will be "1.0" as there is only one element in the array.

For more Practice: Solve these Related Problems:

• Save a NumPy array to a text file using a custom delimiter and verify the contents by reloading the file.
• Create a function that writes an array to a text file with specific formatting for each element.
• Handle large arrays by measuring the time taken to save and load the data from the text file.
• Compare the output file with the original array by reading line by line and checking for consistency.

Python-Numpy Code Editor: