Write newline to csv in Python

Question

I want to end each interation of a for loop with writing a new line of content (including newline) to a csv file. I have this:

# Set up an output csv file with column headers
with open('outfile.csv','w') as f:
    f.write("title; post")
    f.write("\n")

This does not appear to write an actual \n (newline) the file. Further:

    # Concatenate into a row to write to the output csv file
    csv_line = topic_title + ";" + thread_post
    with open('outfile.csv','w') as outfile:
                 outfile.write(csv_line + "\n")

This, also, does not move the cursor in the outfile to the next line. Each new line, with every iteration of the loop, just overwrites the most recent one.

I also tried outfile.write(os.linesep) but did not work.

Answer 1

change 'w' to 'a'

with open('outfile.csv','a')

Answer 2

with open('outfile.csv', 'w', newline='') as f:
    f.writerow(...)

Alternatively:

f = csv.writer('outfile.csv', lineterminator='\n')