Process very large (>20GB) text file line by line

Question

I have a number of very large text files which I need to process, the largest being about 60GB.

Each line has 54 characters in seven fields and I want to remove the

Answer 1

Heres the code for loading text files of any size without causing memory issues. It support gigabytes sized files. It will run smoothly on any kind of machine, you just need to configure CHUNK_SIZE based on your system RAM. More the CHUNK_SIZE, more will be the data read at a time

https://gist.github.com/iyvinjose/e6c1cb2821abd5f01fd1b9065cbc759d

download the file data_loading_utils.py and import it into your code

usage

import data_loading_utils.py.py
file_name = 'file_name.ext'
CHUNK_SIZE = 1000000


def process_lines(line, eof, file_name):

    # check if end of file reached
    if not eof:
         # process data, data is one single line of the file

    else:
         # end of file reached

data_loading_utils.read_lines_from_file_as_data_chunks(file_name, chunk_size=CHUNK_SIZE, callback=process_lines)

process_lines method is the callback function. It will be called for all the lines, with parameter line representing one single line of the file at a time.

You can configure the variable CHUNK_SIZE depending on your machine hardware configurations.