review of python vikend task.

vikend_task.py

#!/usr/bin/env python3

import sys
import re
import datetime


# "kernel" of this script
# i use many parameters, so it's memory intensive, but i start this function recursively so i need it
def heart_of_script(data, which, length, string, future_destination, future_arrival_date, future_arrival_time,
                    future_test_string, switch, lst, connection_to_next):
    # divide data
    source = data[which][0]
    destination = data[which][1]
    departure = data[which][2]
    arrival = data[which][3]
    flight_number = data[which][4]
    # you can flight only from place where you come
    if future_destination == source:
        # you need find right time and date
        time_now = regex_time(departure)
        date_now = regex_date(departure)
        # solve date overflow
        return_value = date_solver(date_now, future_arrival_date)
        if return_value == 0:
            if time_solver(time_now, future_arrival_time, False):
                # you need list to determine if you flight to circle
                lst.extend([source, destination])
                if not fly_to_circle(lst):
                    # you board to plane so I need set your next data
                    # and write it to your diary(string)
                    string += source + "," + destination + "," + departure + "," + arrival + "," + flight_number + "\n"
                    connection_to_next += 1
                    future_destination = destination
                    future_arrival_time = regex_time(arrival)
                    future_arrival_date = regex_date(arrival)
        elif return_value == 1:
            if time_solver(time_now, future_arrival_time, True):
                # you board to plane so I need set your next data
                # and write it to your diary(string)
                lst.extend([source, destination])
                if not fly_to_circle(lst):
                    string += source + "," + destination + "," + departure + "," + arrival + "," + flight_number + "\n"
                    connection_to_next += 1
                    future_destination = destination
                    future_arrival_time = regex_time(arrival)
                    future_arrival_date = regex_date(arrival)
    # you go from start of input to the end
    if which != (length-1):
        which += 1
        heart_of_script(data, which, length, string, future_destination, future_arrival_date, future_arrival_time,
                        future_test_string, switch, lst, connection_to_next)
    # but you can forget on something so you need check it again
    # you need switch because when you start with 5 flight, in input list first 4 flight can be acceptable for you
    # and you need check if you find in next iteration next acceptable flight if don't your journey will end
    # and you can write your diary
    else:
        if switch:
            switch = False
            future_test_string = string
            heart_of_script(data, 0, length, string, future_destination, future_arrival_date, future_arrival_time,
                            future_test_string, switch, lst, connection_to_next)
        elif future_test_string != string:
            future_test_string = string
            heart_of_script(data, 0, length, string, future_destination, future_arrival_date, future_arrival_time,
                            future_test_string, switch, lst, connection_to_next)
        else:
            # print(connection_to_next)
            if connection_to_next != 0:
                print(string)


# every time you can flight at least one time, first time
def first_flight(data, length):
    # first flight can be everyone flight from input list
    for i in range(length):
        string = ""
        lst = []
        future_destination = data[i][1]
        future_arrival_time = regex_time(data[i][3])
        future_arrival_date = regex_date(data[i][3])
        string += data[i][0] + "," + data[i][1] + "," + data[i][2] + "," + data[i][3] + "," + data[i][4] + "\n"
        lst.extend([data[i][0], future_destination])
        heart_of_script(data, i, length, string, future_destination, future_arrival_date, future_arrival_time,
                        string, True, lst, 0)


# if date is same you know compare time but if is next day you need check it
def date_solver(date, f_date):
    if date.year == f_date.year and date.month == f_date.month and date.day == f_date.day:
        return 0
    elif (date.day - f_date.day) == 1:
        return 1
    else:
        return 2


# time solver solve if another plane will go between 1 and 4 hours
# problem, plane can go next day if you arrival time is late at night, so day can overflow
# i can solve it with less magic numbers but this was the task
def time_solver(time, f_time, overflow):
    if overflow:
        j = 0
        f_lst_of_hours = [20, 21, 22, 23]
        lst_of_hours = [0, 1, 2, 3]
        for item in range(len(f_lst_of_hours)):
            j += 1
            if f_time.hour == f_lst_of_hours[item]:
                for i in range(j):
                    if lst_of_hours[i] == time.hour:
                        if time.minute > f_time.minute and j == 4:
                            return False
                        elif time.minute < f_time.minute and i == 0:
                            return False
                        else:
                            return True
        return False

    else:
        if 1 < (time.hour - f_time.hour) <= 4:
            if time.minute > f_time.minute and (time.hour - f_time.hour) == 4:
                return False
            elif time.minute < f_time.minute and (time.hour - f_time.hour) == 1:
                return False
            else:
                return True
        else:
            return False


# divide departure and arrival on only date for easier work with date,if format is not right error
def regex_date(data):
    regex_dater = re.search(r'^[0-9]{4}-[0-9]{2}-[0-9]{2}', data, re.M)
    if regex_date:
        date_almost = regex_dater.group()
        date = datetime.datetime.strptime(date_almost, '%Y-%m-%d').date()
        return date
    else:
        return sys.stderr.write("BAD FORMAT OF DATE")


# divide departure and arrival on only time for easier work with time, if format is not right error
def regex_time(data):
    regex_timer = re.search(r'[0-9]{2}:[0-9]{2}:[0-9]{2}$', data, re.M)
    if regex_time:
        time_almost = regex_timer.group()
        time = datetime.datetime.strptime(time_almost, '%H:%M:%S').time()
        return time
    else:
        return sys.stderr.write("BAD FORMAT OF TIME")


# you can flight from point A->B and back to A but you can't flight A->B->A->B
# in list you have source and destination [A, B, B, A, A, B] and I compare A's and B's and you need minimal 6 to circle

def fly_to_circle(lst):
    if len(lst) >= 6:
        for i in range(len(lst)-6+1):
            if lst[i] == lst[i+3] and lst[i] == lst[i+4] and lst[i+3] == lst[i+4]:
                if lst[i+1] == lst[i+2] and lst[i+1] == lst[i+5] and lst[i+2] == lst[i+5]:
                    return True
                else:
                    return False
            else:
                return False
    else:
        return False


def del_first_and_last_line(s):
    s = s.split('\n', 1)[-1]
    if s.find('\n') == -1:
        return ''
    return s.rsplit('\n', 1)[0]


# DESCRIPTION:
# so i start this program in this format: cat input.csv | python3 python_task.py
# I find all combinations of flight split by new line and this combinations are separated by another new line
# I hope the format is right in input, I don't solve really long lines and problems with input file (i need learn how)
input_string = ""
for line in sys.stdin:
    input_string += str(line)

my_data = [x.split(',') for x in input_string.split('\n')]
del my_data[-1]  # because every file ends with \n i need cut off
length_of_list = len(my_data)
first_flight(my_data, length_of_list)

Since gist still doesn't support line comments ill just write some general points here.

Some general things to read/watch:
tutorialspoint
codestyle
python in one video
python the hard way

Google everything.

Don't use recursion unless its really necessary or you are in the school every recursive program has an iterative solution.

Learn how to use dictionaries, exceptions, try-except and built-in functions.

Plz no heart_of_script or kernel.

Use pythonic for cycles as you did on 182, if you need index use enumerate().

If you don't find something in the build-in functions, google it and pip it;).