yielding.py

#!/usr/bin/python
#
# https://realpython.com/introduction-to-python-generators/
#
LARGE_FILE = "/home/ounis/pyapps/LARGE_FILE_4_TEST"
import os
import sys
from time import sleep
import random

def gen_unexpected_err():
    while True:
        pass

def wiatraczek():
    for i in range(616):
        sys.stderr.write("*{}\r".format(i))
        sys.stderr.flush()
        sleep(.005)
    print()


def csv_yielder(file_name):
    wiatraczek = ["-", "\\", "|", "/", "-", "\\", "|", "/"]
    rows = 0
    lst = []
    for _ in open(file_name):
        # rows += 1
        # sys.stdout.write("Lines: {}\r".format(rows))
        # sys.stdout.flush()
        yield _
        # if rows > 1000000:
        #     # ...
        #     break
    ...

def csv_reader(file_name):
    file = open(file_name)

    try:
        result = file.read().split("\n")
    except Exception as err:
        if isinstance(err, MemoryError):
            result = {"err_desc": [616, "memory error!!!"]}
        else:
            result = {"err_desc": [-1, "some unexpected error... {}".format(repr(err))]}


    return result


def load_file():
    print("Loading...")
    # csv_gen = csv_reader(LARGE_FILE)
    csv_gen = csv_yielder(LARGE_FILE)
    rows = 0
    if isinstance(csv_gen, dict):
        print(csv_gen.get("err_desc")[1])
    else:
        for row in csv_gen:
            rows += 1

    print("\nRow count: {0}".format(rows))


# wiatraczek()
load_file()

#  3674161
# 64186394
#   262441