AttributeError：对象没有属性打印

Question

In Microsoft Visual Studio, I am getting the error "Artist object has no attribute "object". What am I doing wrong? Here is my python code:

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

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

    def printLists(self):
        print('Songs by {}'.format(self.name))
        for alb in self.name:
            alb.printFunct('Songs by {}'.format(self.name))

class Album:
    #define what is in the album
    def __init__(self, albumTitle, artist):
        self.songs = []
        self.albumTitle = albumTitle
        artist.add_album(self)
        self.cls = albumTitle     

        artist.add_album(self)

    def addSongs(self, songTitle):
        self.songs.append(songTitle)

    def printFunct(self):
            for song in self.songs:
                print('{}({})'.format(song.nameSong, self.albumTitle))

class Song:

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

        album.addSongs(self)

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

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

    def printSongs(self):
        print(self.name)
        for song in self.songs:
            print('{}'.format(song.title))

hueyLewis = Artist( "Huey Lewis and the News" )
hallAndOats = Artist( "Hall and Oates" )
toto = Artist( "Toto" )
bigBamBoom = Album( "Big Bam Boom", hallAndOats )
sports = Album( "Sports", hueyLewis )
theSeventhOne = Album( "The Seventh One", toto )
four = Album( "IV", toto )

s1 = Song( "If This is it", sports )
s2 = Song( "Bad is Bad", sports )
s3 = Song( "Out of Touch", bigBamBoom )
s4 = Song( "Did it in a minute ", bigBamBoom )
s5 = Song( "Pamela", theSeventhOne )
s6 = Song( "Africa", four )


myAwesomePlaylist = Playlist( "My Awesome Playlist " )
myAwesomePlaylist.addSongs( s1 )
myAwesomePlaylist.addSongs( s2 )
myAwesomePlaylist.addSongs( s3 )
myAwesomePlaylist.addSongs( s4 )
myAwesomePlaylist.addSongs( s5 )
myAwesomePlaylist.addSongs( s6 )
hallAndOats.print('Songs by {}'.format(self.name))
hueyLewis.print('Songs by {}'.format(self.name))
toto.print('Songs by {}'.format(self.name))
myAwesomePlaylist.print()

The output is supposed to print out the artist and the song of the artist etc.

Answer 1

You don't define a print method for any of your classes. Therefore, the objects created by those classes won't have a print attribute. I believe this is what you wanted though:

hallAndOats.printLists()
hueyLewis.printLists()
toto.printLists()
myAwesomePlaylist.printSongs()

EDIT

You have two separate mistakes in Artist.printLists() . That method should look like this:

def printLists(self):
    print('Songs by {}'.format(self.name))
    for alb in self.albums:
        alb.printFunct()

You were iterating through the individual characters in the name of the artist instead of the albums that the artist produced. Also, you were calling Album.printFunct() incorrectly. As you defined it, it does not have any explicit parameters, yet you were calling it with 'Songs by {}'.format(self.name) as an explicit argument.

EDIT 2

You have yet another error in your code, but this time in Album.printFunct() . That method should look like this:

def printFunct(self):
    for song in self.songs:
        print('{}({})'.format(song.title, self.albumTitle))

You were using song.nameSong , which appears nowhere else in your code (least of all as an instance variable of Song ).

EDIT 3

You have another error in Album.__init__ . You are adding every album to each artist twice. Remove one of the artist.add_album(self) s from the Album constructor to fix this.

Answer 2

Your error tells you something: Artist objects don't have the attribute print . They have printLists . Just change those last lines to use printLists instead of print . The playlist, however, should be printSongs .

Answer 3

I believe the error is from here:

hallAndOats.print('Songs by {}'.format(self.name))
hueyLewis.print('Songs by {}'.format(self.name))
toto.print('Songs by {}'.format(self.name))
myAwesomePlaylist.print()

You should use

.printLists for class 'Artist',

.printFunct for class 'Album' and

.printSongs for class 'Playlist'

You can only use the functions you have defined in you class. Hope it helps. :)

Answer 4

您需要在Artist对象上调用printLists() 。

Answer 5

I'd urge you to have a look at How to create a Minimal, Complete, and Verifiable example . In this case, you could have whittled your code all the way down to this and still had the same problem:

class Artist:
    def __init__(self, name):
        self.name = name
        self.albums = []
    def add_album(self, album):
        self.albums.append(album)
    def printLists(self):
        print('Songs by {}'.format(self.name))
        for alb in self.name:
            alb.printFunct('Songs by {}'.format(self.name))

hallAndOats = Artist( "Hall and Oates" )

hallAndOats.print('Songs by {}'.format(self.name))

From there, it should be pretty clear that the reason for the error is that you didn't define a method called print on Artist objects.

(Also, in the future, please provide the full traceback so that people can see exactly what and where the exception is.)