Dobry. Mam tutaj kod i nie rozumiem jego części
class Song:
"""Class to represent a song
Attributes:
title (str): The title of the song
artist (Artist): An artist object representing the songs creator.
duration (int): The duration of the song in seconds. May be zero
"""
def __init__(self, title, artist, duration=0):
self.title = title
self.artist = artist
self.duration = duration
class Album:
""" Class to represent an Album, using it's track list
Attributes:
name (str): The name of the album.
year (int): The year was album was released.
artist: (Artist): The artist responsible for the album. If not specified,
the artist will default to an artist with the name "Various Artists".
tracks (List[Song]): A list of the songs on the album.
Methods:
add_song: Used to add a new song to the album's track list.
"""
def __init__(self, name, year, artist=None):
self.name = name
self.year = year
if artist is None:
self.artist = Artist("Various Artists")
else:
self.artist = artist
self.tracks = []
def add_song(self, song, position=None):
"""Adds a song to the track list
Args:
song (Song): A song to add.
position (Optional[int]): If specified, the song will be added to that position
in the track list - inserting it between other songs if necessary.
Otherwise, the song will be added to the end of the list.
"""
if position is None:
self.tracks.append(song)
else:
self.tracks.insert(position, song)
class Artist:
"""Basic class to store artist details.
Attributes:
name (str): The name of the artist.
albums (List[Album]): A list of the albums by this artist.
The list includes only those albums in this collection, it is
not an exhaustive list of the artist's published albums.
Methods:
add_album: Use to add a new album to the artist's albums list
"""
def __init__(self, name):
self.name = name
self.albums = []
def add_album(self, album):
"""Add a new album to the list.
Args:
album (Album): Album object to add to the list.
If the album is already present, it will not added again (although this is yet to implemented).
"""
self.albums.append(album)
def load_data():
new_artist = None
new_album = None
artist_list = []
with open("albums.txt", "r") as albums:
for line in albums:
# data row should consist of (artist, album, year, song)
artist_field, album_field, year_field, song_field = tuple(line.strip('\n').split('\t'))
year_field = int(year_field)
print("{}:{}:{}:{}".format(artist_field, album_field, year_field, song_field))
if new_artist is None:
new_artist = Artist(artist_field)
elif new_artist.name != artist_field:
# We've just read details for a new artist
# store the current album in the currents artists collection then create a new artist object
new_artist.add_album(new_album)
artist_list.append(new_artist)
new_artist = Artist(artist_field)
new_album = None
if new_album is None:
new_album = Album(album_field, year_field, new_artist)
elif new_album.name != album_field:
# We've just read a new album for the current artist
# store the current album in the artist's collection then create a new album object
new_artist.add_album(new_album)
new_album = Album(album_field, year_field, new_artist)
# create a new song object and add it to the current album's collection
new_song = Song(song_field, new_artist)
new_album.add_song(new_song)
# After read the last line of the text file, we will have an artist and album that haven't
# been store - process them now
if new_artist is not None:
if new_album is not None:
new_artist.add_album(new_album)
artist_list.append(new_artist)
return artist_list
def create_checkfile(artist_list):
"""Create a check file from the object data for comparison with the original file"""
with open("checkfile.txt", 'w') as checkfile:
for new_artist in artist_list:
for new_album in new_artist.albums:
for new_song in new_album.tracks:
print("{0.name}\t{1.name}\t{1.year}\t{2.title}".format(new_artist, new_album, new_song),
file=checkfile)
if __name__ == '__main__':
artists = load_data()
print("There are {} artists".format(len(artists)))
create_checkfile(artists)
Kompletnie nie rozumiem cześci od 91 do 107. Bylby ktos w stanie mi to wyjaśnić ?
Python 
