CODEWITHSUNDEEP
python
Yoan Herrera
Yoan Herrera

Reputation: 29

For loop on a dictionary giving out of range error

I'm having troubles understanding dictionaries and for loop. I have this example that takes a nested dictionary representing a playlist of songs. On the first example the code runs just fine, but when I try to create a function and try to clean up the code. It keeps saying index out of range. Can anybody throw their 2 cents.

Example playlist from a JSON file:

playlist = {
        'title': 'faves',
        ' author': 'Me', 
        'songs': [
        {
            'title': 'song1',
            'artist': ['john', 'smith'],
            'genre': 'Pop',
            'duration' : 3.23
        },
        {
            'title': 'song2',
            'artist': ['john2'],
            'genre': 'Rock',
            'duration' : 3.45
        },
        {
            'title': 'song3',
            'artist': ['john3', 'smith3'],
            'genre': 'Jazz',
            'duration' : 2.45
        }
    ]
}

This first code byte works well and print the right strings.

sa =  f" and {song['artist'][1]}"
for song in playlist['songs']:
    print(f"{song['title']} by {song['artist'][0]}{sa if len(song['artist']) >= 2 else ''}, runtime: {song['duration']}, genre: {song['genre']}")

But here when I try to run this it says index out of range. It's calling artist_two, but is not supposed to do that unless there is more than one artist for a song. 

def print_playlist(songs):
    print(songs)
    for song in songs:

        title = song['title']
        duration = song['duration']
        genre = song['genre']
        artists = song['artist']
        artist_one = song['artist'][0]
        artist_two = song['artist'][1]
        sa =  f" and {artist_two}"


        print(f"{title} by {artist_one}{sa if len(artists) >=2 else ''}, runtime: {duration}, genre: {genre}")

print_playlist(playlist['songs'])

Upvotes: 1

Views: 71

Answers (2)

Yoan Herrera
Yoan Herrera

Reputation: 29

Thank you Zack Tarr

final code looks like 

def print_playlist(songs):
for song in songs:

    title = song['title']
    duration = song['duration']
    genre = song['genre']
    artists = song['artist']

    artist_plus = " and ".join( artist for artist in artists)


    print(f" {title} by {artist_plus if len(artists) >= 2 else artists[0]}, runtime: {duration}, genre: {genre}")

print_playlist(playlist['songs'])

Upvotes: 0

Zack Tarr
Zack Tarr

Reputation: 851

You can use this method to make a string of the names with " and " in between them. 

artist_list=["John","Smith"]

y=" and ".join(str(x) for x in artist_list)

print(y)

This give the output of John and Smith

And if you make the artist list: ["John","Smith","Dave"] Your output will look like John and Smith and Dave

As mentioned in the comment above, you are assuming there are always at least 2 elements in the artist_list. You should rather use an approach like mine that I found from Concatenate item in list to strings

Upvotes: 1

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