How To Save An Array in Python

• Save array in python using NumPy Library

  Install numpy using terminal

  pip install numpy
  

  Example code to save array in a file using NumPy

  import numpy as np
    
  a = np.arange(10)
  print(a)
  np.save('pythonfile', a)
    
  print("the array is saved in the file pythonfile.npy")
  

  Output:

  [0 1 2 3 4 5 6 7 8 9 10]

  You can save numpy array to a file using numpy.save() method and then later, load into an array using numpy.load().

• Save an array into a CSV file in python using numpy

  You have to use np.tofile() function to write Python array into CSV file. Install numpy library using below command before using it.

  pip install numpy
  

  Create a main.py file and add below code in it.

  import numpy as np
  
  arr = np.asarray([ [7,8,9], [5,8,9] ])
  arr.tofile('sample.csv', sep = ',')
  

  Create sample.csv file and Run python main.py in terminal to add array to csv file in python.

• Save an array in a csv file using numpy with panda dataframe

  You have to create a main.py and sample-pddf.csv file in root directory. Before using numpy and pandas library you have to install it using pip install command. Now you have to run python main.py in your terminal to save array to csv file using numpy and padas dataframe.

  Run below command in your terminal before using numpy and pandas library.

  pip install numpy
  
  pip install pandas
  

  **main.py**

  import numpy as np
  import pandas as pd
  
  arr = np.asarray([ [7,8,9], [5,8,9] ])
  pd.DataFrame(arr).to_csv('sample-pddf.csv', index_label = "Index", header  = ['a','b','c'])
  

• Save a Python list to a file

  Create list names = ['John', 'Doe', 'Bob'].

  Open file in write mode eg: with open(r'./info.txt', 'w') as fp:.

  Iterate list using a for loop for item in names:.

  Write List item to info.txt file fp.write("%s\n" % item).

• How do I save an array as a text in Python?

  Use numpy.savetxt() to save an array to a text file.

  First import numpy library in python using command in terminal - pip install numpy.

  Open file in write mode >> a_file = open("test.txt", "w")

  Loop array >> for row in an_array:

  Save data in file >> np.savetxt(a_file, row)

  Close file >> a_file.close()

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