how to write in csv files in python code example

Example 1: create csv file python

# This action requires the 'csv' module
import csv

# The basic usage is to first define the rows of the csv file:
row_list = [["SN", "Name", "Contribution"],
             [1, "Linus Torvalds", "Linux Kernel"],
             [2, "Tim Berners-Lee", "World Wide Web"],
             [3, "Guido van Rossum", "Python Programming"]]

# And then use the following to create the csv file:
with open('protagonist.csv', 'w', newline='') as file:
    writer = csv.writer(file)
    writer.writerows(row_list)
# This will create a csv file in the current directory

Example 2: array storing in csv file by python

# long arrays can be stored in csv files far more efficiently
import numpy as np
import csv

# uploading arrays in a csv file
arr1 = [i for i in range(500)]
arr2 = [i for i in range(1000)]
arr3 = [i for i in range(2000)]
# you can write('w') or append('a')
with open('record.csv', 'a') as record_append:
    np.savetxt(record_append, np.asarray([arr1]), delimiter=',')
    np.savetxt(record_append, np.asarray([arr2]), delimiter=',')
    np.savetxt(record_append, np.asarray([arr3]), delimiter=',')

# downloading them from the csv file
two_dim_arr = []  # each line of the file is an array element
with open('record.csv', 'r') as record_read:
    reader = csv.reader(record_read)
    for i, each_arr in enumerate(reader):
        two_dim_arr.append([eval(each) for each in each_arr])
        
# printing the arrays in lines
for each_line in two_dim_arr:
  print(each_line)

Example 3: python save as csv

import numpy as np
np.savetxt('data.csv', (col1_array, col2_array, col3_array), delimiter=',')

Example 4: Write a table to CSV file python

header = [re.sub(' +',' ',i[0][:-1].replace('\n', ' ')) for i in optionsTable[0]]

with open('test.csv', 'w') as fp:
   writer = csv.writer(fp, delimiter=',')
   writer.writerow(header)
   for row in optionsTable:
      writer.writerow([i[1] for i in row])

#Credit to https://stackoverflow.com/users/790387/burhan-khalid Burhan Khalid
#On StackOverflow.