CODEWITHSUNDEEP
pythoncsvappendexport-to-csv
Alex22
Alex22

Reputation: 39

Appending data to CSV repeatedly

I have a list of values that I am trying to append to a csv file every time my program runs but my code only appends once and never again. What am I doing wrong here.

import random
import csv
import numpy as np
from csv import writer

randomlist = []
for i in range (0,5):
    n = random.randint(1,30)
    randomlist.append(n)
print(randomlist)

np.savetxt("test.csv",  
           randomlist,
           fmt ='% s') 

def append_list_as_row(file_name, list_of_elem):
       with open(file_name, 'a+', newline='') as file:
                csv_writer = writer(file)
                csv_writer.writerow(list_of_elem)      

append_list_as_row('test.csv',randomlist)

Upvotes: 0

Views: 127

Answers (2)

Atheer
Atheer

Reputation: 85

The problem is you're saving a new "test.csv" file everytime you run the code with the function np.savetxt.

Try separating this part of the code:

np.savetxt("test.csv",  
           randomlist,
           fmt ='% s')

from the rest of the code, let it run only once

Upvotes: 1

Douglas Jovenil
Douglas Jovenil

Reputation: 303

When you call np.savetxt("test.csv", randomlist, fmt ='% s'), this method overrides test.csv, so just don't call it, you can do something like:

from csv import writer
import numpy as np 
import random
import csv


def main():
  randomlist = []
  for i in range (0,5):
    n = random.randint(1,30)
    randomlist.append(n)
  print(randomlist)

  # np.savetxt("test.csv", randomlist, fmt ='% s') 
  append_list_as_row('test.csv', randomlist)

def append_list_as_row(file_name, list_of_elem):
  with open(file_name, 'a+', newline='') as file:
    csv_writer = writer(file)
    csv_writer.writerow(list_of_elem)   


if __name__ == '__main__':
  main()

Upvotes: 2

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