python - What's the most optimal way to rewrite headers of a very big csv file?

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65937479/whats-the-most-optimal-way-to-rewrite-headers-of-a-very-big-csv-file

Answer 1

Assuming your csv is a line by line file (Obviously), the file object reader already has this option :

for line in open('your_really_very_so_big_file.csv'):
    process_data(line)

However this for read only, if you wanna write you have to read the whole stream. However, one of the good tips for your case is a copy paste after editing, something like:

source.readline() 
destination.write(edited_line)
shutil.copyfileobj(source, destination)

EDIT :

Similar answer here: shutil.copyfileobj

Doc: shutil.copyfileobj