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How to save a NumPy array to a text file?
  • Last Updated : 18 Jun, 2021

Let us see how to save a numpy array to a text file.

Method 1: Using File handling 
Creating a text file using the in-built open() function and then converting the array into string and writing it into the text file using the write() function. Finally closing the file using close() function. Below are some programs of the this approach: 

  • Example 1: 

Python3




# Program to save a NumPy array to a text file
 
# Importing required libraries
import numpy
 
# Creating an array
List = [1, 2, 3, 4, 5]
Array = numpy.array(List)
 
# Displaying the array
print('Array:\n', Array)
file = open("file1.txt", "w+")
 
# Saving the array in a text file
content = str(Array)
file.write(content)
file.close()
 
# Displaying the contents of the text file
file = open("file1.txt", "r")
content = file.read()
 
print("\nContent in file1.txt:\n", content)
file.close()
  • Output: 
Array:
 [1 2 3 4 5]

Content in file1.txt:
 [1 2 3 4 5]
  • Example 2: 

Python3




# Program to save a NumPy array to a text file
 
# Importing required libraries
import numpy
 
# Creating 2D array
List = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Array = numpy.array(List)
 
# Displaying the array
print('Array:\n', Array)
file = open("file2.txt", "w+")
 
# Saving the 2D array in a text file
content = str(Array)
file.write(content)
file.close()
 
# Displaying the contents of the text file
file = open("file2.txt", "r")
content = file.read()
 
print("\nContent in file2.txt:\n", content)
file.close()
  • Output: 
Array:
 [[1 2 3]
 [4 5 6]
 [7 8 9]]

Content in file2.txt:
 [[1 2 3]
 [4 5 6]
 [7 8 9]]
  • Method 2:

Using NumPy functions



After creating the array, the 

numpy.savetxt()

function can be used to save the array into a text file. Below are some programs of this approach.

  • Example 1: 

Python3




# Program to save a NumPy array to a text file
 
# Importing required libraries
import numpy
 
# Creating an array
List = [1, 2, 3, 4, 5]
Array = numpy.array(List)
 
# Displaying the array
print('Array:\n', Array)
 
# Saving the array in a text file
numpy.savetxt("file1.txt", Array)
 
# Displaying the contents of the text file
content = numpy.loadtxt('file1.txt')
print("\nContent in file1.txt:\n", content)
  • Output: 
Array:
 [1 2 3 4 5]

Content in file1.txt:
 [1. 2. 3. 4. 5.]
  • Example 2: 

Python3




# Program to save a NumPy array to a text file
 
# Importing required libraries
import numpy
 
# Creating 2D array
List = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
Array = numpy.array(List)
 
# Displaying the array
print('Array:\n', Array)
 
# Saving the 2D array in a text file
numpy.savetxt("file2.txt", Array)
 
# Displaying the contents of the text file
content = numpy.loadtxt('file2.txt')
print("\nContent in file2.txt:\n", content)
  • Output: 
Array:
 [[1 2 3]
 [4 5 6]
 [7 8 9]]

Content in file2.txt:
 [[1. 2. 3.]
 [4. 5. 6.]
 [7. 8. 9.]]

 

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