How to add specific elements from list of lists in Python-CodePudding

Let's say I have the following list that contains other lists:

episodes = [
['1', '2', '3', '4', '5', '6', '7'], 
['1', '2', '3', '4', '5', '1', '2', '3', '4', '5', '6'], 
['1', '2', '3', '1', '2', '3', '4', '5', '6', '1', '2', '3', '4', '5', '6', '1', '2', '3', '4', '1', '2', '3']
]

Each list refer to episodes of TV-shows. For example, the first list has one season with 7 episodes, whereas the last list has five seasons with season one having 3 episodes, season 2 6 episodes and so on. I would like to save the total number of episodes for each TV-show by adding the total number of episodes for each season of the TV-show. In other words, first list is just taking the last element of that list, but the last list I have to add 3 & 6 & 6 & 4 & 3. I hope you understand what I'm trying to do. I thought about using indexing and see where the element "1" lies in each list with more than one season so I can choose the element before (number of episodes of previous season) and so one. But it gets a bit tricky doing it for all other seasons as well.

CodePudding user response：

If I understand you correctly you can just sum up the length of each list, i.e. sum(map(len, episodes))?

CodePudding user response：

if you just want the total number of episodes regardless of seasons just count the length of the each show list.

episodes = [
['1', '2', '3', '4', '5', '6', '7'], 
['1', '2', '3', '4', '5', '1', '2', '3', '4', '5', '6'], 
['1', '2', '3', '1', '2', '3', '4', '5', '6', '1', '2', '3', '4', '5', '6', '1', '2', '3', '4', '1', '2', '3']
]

print(*[len(show) for show in episodes], sep="\n")

OUTPUT

7
11
22

CodePudding user response：

I came up with something like this to check for number of episodes in each season:

episodes = [
    ['1', '2', '3', '4', '5', '6', '7', "8", "9", "10", "11"],
    ['1', '2', '3', '4', '5',
     '1', '2', '3', '4', '5', '6'],
    ['1', '2', '3',
     '1', '2', '3', '4', '5', '6',
     '1', '2', '3', '4', '5', '6',
     '1', '2', '3', '4',
     '1', '2', '3']
]


def count_episodes(list_of_episodes):
    all_episodes = [e for l in list_of_episodes for e in l]
    previous_episode = 0
    season = 1
    seasons = {}
    tmp_list = []

    for i in all_episodes:
        if previous_episode > int(i):
            seasons["season " str(season)] = tmp_list
            tmp_list = []
            season  = 1
        previous_episode = int(i)
        tmp_list.append(i)

    if len(tmp_list) > 0:
        seasons["season " str(season)] = tmp_list

    for i in seasons:
        print(i   " has {} episodes".format(len(seasons[i])))


count_episodes(episodes)

OUTPUT

season 1 has 11 episodes
season 2 has 5 episodes
season 3 has 6 episodes
season 4 has 3 episodes
season 5 has 6 episodes
season 6 has 6 episodes
season 7 has 4 episodes
season 8 has 3 episodes

CodePudding user response：

The other answers are just adding total episodes of each show. IIRC, I think you want the episode count of each season of each show:

import numpy as np
output = []
for tv_show in episodes:
    arr = np.array(tv_show)
    output.append(arr[np.where(arr=='1')[0][1:]-1].astype(int).tolist()   [int(arr[-1])])

Output:

[[7], [5, 6], [3, 6, 6, 4, 3]]

CodePudding user response：

simpler solution

At the end, it is sth as simple as:

list(map(len, episodes))
## [7, 11, 22]

If all episodes are listed always, then you can just count the total number of episodes - it will be always the same as if you determined the maximum numbers and summed them up.

slighlty more elaborate solution

from functools import reduce

def list_to_max_seasons(lst, first_element='1'):
    return reduce(lambda l, x: l   [x] if x == first_element else l[:-1]   [x], lst, [])

def sum_max_episodes(lol):
     return [(lambda l: sum([int(x) for x in l]))(list_to_max_seasons(il)) for il in lol]

Test by:

sum_max_episodes(episodes)
## [7, 11, 22]

more elaborate (recursive) solution

These solutions are not very pythonic, I admit. But they are quite universal.

def list_to_seasons(l, acc=[], by='1', tmp=[]):
    if l == []:
        return acc [tmp]
    elif l[0] == by:
        if tmp == []:
            return list_to_seasons(l[1:], acc=[], by=by, tmp=[l[0]])
        else:
            return list_to_seasons(l[1:], acc=acc [tmp], by=by, tmp=[l[0]])
    else:
        return list_to_seasons(l[1:], acc=acc, by=by, tmp=tmp [l[0]])


list_to_seasons(['1','2','3','1','2','1','2','3','1','1'])
## [['1', '2', '3'], ['1', '2'], ['1', '2', '3'], ['1'], ['1']]

Or:

def list_to_max_seasons(l, acc=[], by='1', last=None):
    if l == []:
        return acc [last]
    elif l[0] == by:
        if last is None:
            return list_to_max_seasons(l[1:], acc=[], by=by, last=l[0])
        else:
            return list_to_max_seasons(l[1:], acc=acc [last], by=by, last=l[0])
    else:
        return list_to_max_seasons(l[1:], acc=acc, by=by, last=l[0])
list_to_max_seasons(['1','2','3','1','2','1','2','3','1','1'])
## ['3', '2', '3', '1', '1']

Then:

def sum_max_episodes(lol):
     return [(lambda l: sum([int(x) for x in l]))(list_to_max_seasons(il)) for il in lol]

Test by:

sum_max_episodes(episodes)
## [7, 11, 22]