Add delimiters while writing into a text file

Question

I am writing an array into the text file, which I later use to read in excel for plotting. The data file is split in such a way that after 1000000 steps (approximately), the file closes and starts writing to another file.

However, my text file is writing data as a big chunk of values without any separators. Please refer the code below and let me know where I am going wrong.

counter = 1
for i in range(0, len(abc_value), 1000000):
    with open(f"abc{counter}.txt", "w") as file:
        for val in abc_value[i:i + 1000000]:
            file.write(str(val))
        file.close()
        counter += 1

Thank you!

Make use of https://docs.python.org/3/library/csv.html#csv.writer or use writeline() rather than write. — lllrnr101, Feb 10 '21 at 19:25
when I use writline(), I get the error "_io.TextIOWrapper' object has no attribute 'writeline" — user1234, Feb 10 '21 at 19:37
Why do you expect it to write any separators when you never ask it to? [How to debug small programs.](//ericlippert.com/2014/03/05/how-to-debug-small-programs/) | [What is a debugger and how can it help me diagnose problems?](//stackoverflow.com/q/25385173/843953) The point about rubber-duck debugging is especially relevant. — Pranav Hosangadi, Feb 10 '21 at 19:40

score 1 · Answer 1 · answered Feb 10 '21 at 19:39

1

Please see example below for using csv writer.

import csv
with open('abc.txt', 'w') as csv_file:
    wrtr = csv.writer(csv_file)
    for val in range(10):
        wrtr.writerow(str(val))

answered Feb 10 '21 at 19:39

lllrnr101

2,288
2
4
15

Thank you for the csv writer tutorial. It is helpful. – user1234 Feb 10 '21 at 19:53

score 1 · Accepted Answer · answered Feb 10 '21 at 19:46

The idea is correct but you are reading the values of the array and they do not have a comma. You have to add the comma when passing the value to string. A simple way to do it would be:

counter = 1
for i in range(0, len(abc_value), 1000000):
    with open(f"hola.txt", "w") as file:
        file.write(str(abc_value[i]))
        for val in abc_value[i+1:i + 1000000]:
            file.write(", " + str(val))
        file.close()
        counter += 1

Add delimiters while writing into a text file

2 Answers2