Addition of floats inside List of dictionaries in dictionary

Question

I am trying to create a for loop for addition of a the variable associated with ‘length’ inside this list of dictionaries in a dictionary. I have searched online for answers, this site included to calculate this addition, but nothing quite matches.
The assignment designates:
This function should return a string, the name of the longest album.

Below is all the information for the albums, and what I have so far. Of course, my way does technically work. I became frustrated with the nested for loops, and couldn’t figure out the correct format. I would like to find the correct way to format the for loop so I can get the same answer without using this repetitive way.
`

from cisc108 import assert_equal
album1={
    'name':'Album1',
    'songs':[{'title':'rock','explicit':True,'length':2.5},
       {'title':'starlight','explicit':False,'length':5.2},
       {'title':'smile','explicit':False,'length':1.75}]
    }

album2={
    'name':'Album2',
    'songs':[{'title':'stone','explicit':False,'length':4.75},
       {'title':'moonlight','explicit':False,'length':3.0},
       {'title':'happy','explicit':True,'length':2.8}]}

def longest_album(A1,A2):
    x1 = A1['songs'][0]['length']
    x2 = A1['songs'][1]['length']
    x3 = A1['songs'][2]['length']
    album_1_len= x1 + x2 + x3
    y1 = A2['songs'][0]['length']
    y2 = A2['songs'][1]['length']
    y3 = A2['songs'][2]['length']
    album_2_len = y1 + y2 + y3
    if album_2_len > album_1_len:
        return A2['name']
    else:
        return A1['name']

assert_equal(longest_album(album1,album2), "Album2")

`

The for loop I began with started as such. I tried a lot of other combinations, but I deleted them many times previously, so I don’t have every exact thing I tried:

`

def longest_album(A1,A2):
    album1 = 0
    album2 = 0
    for i in A1['songs']:
        if i == 'length':
            album1+= i
    for i in A2['songs']:
        if i == 'length':
            album2+= i
    if album2 > album1:
        return A2['name']
    else:
        return A1['name']

‘

When I use a return to statement to see if there are any variables in album1 and album2, I see that they are both 0’s still. I’m hoping this is a simple formatting issue. Thanks again.

Asked By: baylee

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Source

Answer 1

The issue with your 2nd approach is that your for loop iterates over a list of dicts and i == 'length' will just compare a dictionary structure with plain string: that’s always False.
Moreover, we need to also consider a case when two albums would have equal total length.
The optimal solution would be as follows:

def get_longest_album_name(alb_1, alb_2):
    # summing up length of songs
    alb_1_len = sum(s['length'] for s in alb_1['songs'])
    alb_2_len = sum(s['length'] for s in alb_2['songs'])

    if alb_1_len == alb_2_len:
        print('Albums have equal length!')
        return alb_1['name'], alb_2['name']
    elif alb_1_len > alb_2_len:
        return alb_1['name']
    else:
        return alb_2['name']


print(get_longest_album_name(album1, album2))  # Album2

Answered By: RomanPerekhrest

Answer 2

You can put the two albums in a list and then iterate through that list to avoid using two loops:

def longest_album(A1,A2):
    albums = [A1, A2]
    sum = [0, 0]
    for i in range(2):
        for song in albums[i]['songs']:
            sum[i] += song['length']
    if sum[0] > sum[1]:
        return A1['name']
    return A2['name']

Answered By: Allan Rocha Pereira

Answer 3

Would the below achieve the desired result?

album1 = {
    'name': 'Album1',
    'songs': [{'title': 'rock', 'explicit': True, 'length': 2.5},
              {'title': 'starlight', 'explicit': False, 'length': 5.2},
              {'title': 'smile', 'explicit': False, 'length': 1.75}]
}
album2 = {
    'name': 'Album2',
    'songs': [{'title': 'stone', 'explicit': False, 'length': 4.75},
              {'title': 'moonlight', 'explicit': False, 'length': 3.0},
              {'title': 'happy', 'explicit': True, 'length': 2.8}]}


def album_length(album):
    return sum(song["length"] for song in album["songs"])


def longest_album(*albums):
    return sorted(albums, key=album_length, reverse=True)[0]["name"]

assert_equal(longest_album(album1,album2), "Album2")

Answered By: Ilya Nekhay

Addition of floats inside List of dictionaries in dictionary

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