Python 打印对象地址而不是值

Question

我想打印所有已添加到 tracks[] 列表中的轨道。当我尝试这样做时，我得到了该对象在内存中的地址，而不是它的实际值。我显然不明白对象创建/对象从一个类到另一个类的传递是如何工作的。

class Song:

    def __init__(self, title, artist, album, track_number):
        self.title = title
        self.artist = artist
        self.album = album
        self.track_number = track_number

        artist.add_song(self)


class Album:

    def __init__(self, title, artist, year):
        self.title = title
        self.artist = artist
        self.year = year

        self.tracks = []

        artist.add_album(self)

    def add_track(self, title, artist=None):
        if artist is None:
            artist = self.artist

        track_number = len(self.tracks)

        song = Song(title, artist, self, track_number)

        self.tracks.append(song)
        print(self.tracks)


class Artist:
    def __init__(self, name):
        self.name = name

        self.albums = []
        self.songs = []

    def add_album(self, album):
        self.albums.append(album)

    def add_song(self, song):
        self.songs.append(song)


class Playlist:
    def __init__(self, name):
        self.name = name
        self.songs = []

    def add_song(self, song):
        self.songs.append(song)

band = Artist("Bob's Awesome Band")
album = Album("Bob's First Single", band, 2013)
album.add_track("A Ballad about Cheese")
album.add_track("A Ballad about Cheese (dance remix)")
album.add_track("A Third Song to Use Up the Rest of the Space")
playlist = Playlist("My Favourite Songs")


for song in album.tracks:
    playlist.add_song(song)

Answer 1

看起来您正在尝试打印数组，而不是数组中的值。 print(self.tracks) 正在打印 self.tracks 对象，它是一个数组。尝试 print(self.tracks[x])，x 是您要打印的字符串的索引。

如果您想打印该数组中的所有对象，请遍历它并打印每个对象。

使用它遍历数组:

for x in range(len(self.tracks)):
    print self.tracks[x].title

或

for track in self.tracks
    print track.title

要获取每首歌曲对象的标题值，请在循环中使用 track.title 对其进行寻址。要获取艺术家或年份，请将其更改为 track.artist 或 track.year。

您可以使用相同的逻辑构建更大的字符串，例如:print("标题"+ track.title + ", 艺术家"+ track.artist)