How to add list values?

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I have a list of lists, and I wanted to add up the various values for the Indice 3 of each list, but only if there is a certain string in this list. How can I do?

For example I have this list: 

[['ALABAMA', 'Abbeville', 2645, 11, 63], ['ALABAMA', 'Adamsville', 4481, 19, 321], ['ALABAMA', 'Addison', 744, 1, 25], ['ALABAMA', 'Alabaster', 31170, 44, 640], ['ALABAMA', 'Alexander City', 14692, 119, 661], ['ALABAMA', 'Aliceville', 2419, 7, 48], ['ALABAMA', 'Andalusia', 9079, 34, 491], ['ALABAMA', 'Anniston', 22648, 461, 1988], ['ALABAMA', 'Arab', 8295, 32, 640], ['ALABAMA', 'Ardmore', 1304, 2, 31], ['ALABAMA', 'Arley', 353, 3, 27], ['ALABAMA', 'Ashford', 2177, 2, 54], ['ALABAMA', 'Ashland', 1926, 9, 63],['ARIZONA', 'Chandler', 248718, 575, 5900], ['ARIZONA', 'Chino Valley', 10850, 50, 207], ['ARIZONA', 'Clarkdale', 4090, 5, 51], ['ARIZONA', 'Clifton', 3499, 11, 42], ['ARIZONA', 'Coolidge', 11820, 66, 662], ['ARIZONA', 'Cottonwood', 11285, 44, 401], ['ARIZONA', 'Eagar', 5034, 15, 106]]

And the statement says: Determine the name of the state with the most violent crime cases (corresponds to Dice 3).

python python-3.x

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2 answers

1


You can use the function sum(), look at you:

lst = [['ALABAMA', 'Abbeville', 2645, 11, 63], ['ALABAMA', 'Adamsville', 4481, 19, 321], ['ALABAMA', 'Addison', 744, 1, 25], ['ALABAMA', 'Alabaster', 31170, 44, 640], ['ALABAMA', 'Alexander City', 14692, 119, 661], ['ALABAMA', 'Aliceville', 2419, 7, 48], ['ALABAMA', 'Andalusia', 9079, 34, 491], ['ALABAMA', 'Anniston', 22648, 461, 1988], ['ALABAMA', 'Arab', 8295, 32, 640], ['ALABAMA', 'Ardmore', 1304, 2, 31], ['ALABAMA', 'Arley', 353, 3, 27], ['ALABAMA', 'Ashford', 2177, 2, 54], ['ALABAMA', 'Ashland', 1926, 9, 63],['ARIZONA', 'Chandler', 248718, 575, 5900], ['ARIZONA', 'Chino Valley', 10850, 50, 207], ['ARIZONA', 'Clarkdale', 4090, 5, 51], ['ARIZONA', 'Clifton', 3499, 11, 42], ['ARIZONA', 'Coolidge', 11820, 66, 662], ['ARIZONA', 'Cottonwood', 11285, 44, 401], ['ARIZONA', 'Eagar', 5034, 15, 106]]

# Todos os Estados
print sum([ item[3] for item in lst ])

# Alabama
print sum([ item[3] for item in lst if item[0] == 'ALABAMA' ])

# Arizona
print sum([ item[3] for item in lst if item[0] == 'ARIZONA' ])

Exit:

1510
744
766

To determine which is the most violent state, you can implement something like:

lst = [['ALABAMA', 'Abbeville', 2645, 11, 63], ['ALABAMA', 'Adamsville', 4481, 19, 321], ['ALABAMA', 'Addison', 744, 1, 25], ['ALABAMA', 'Alabaster', 31170, 44, 640], ['ALABAMA', 'Alexander City', 14692, 119, 661], ['ALABAMA', 'Aliceville', 2419, 7, 48], ['ALABAMA', 'Andalusia', 9079, 34, 491], ['ALABAMA', 'Anniston', 22648, 461, 1988], ['ALABAMA', 'Arab', 8295, 32, 640], ['ALABAMA', 'Ardmore', 1304, 2, 31], ['ALABAMA', 'Arley', 353, 3, 27], ['ALABAMA', 'Ashford', 2177, 2, 54], ['ALABAMA', 'Ashland', 1926, 9, 63],['ARIZONA', 'Chandler', 248718, 575, 5900], ['ARIZONA', 'Chino Valley', 10850, 50, 207], ['ARIZONA', 'Clarkdale', 4090, 5, 51], ['ARIZONA', 'Clifton', 3499, 11, 42], ['ARIZONA', 'Coolidge', 11820, 66, 662], ['ARIZONA', 'Cottonwood', 11285, 44, 401], ['ARIZONA', 'Eagar', 5034, 15, 106]]

def obterEstadoMaisViolento( lst ):
    d = {}
    for i in lst:
        if( i[0] in d ):
            d[ i[0] ] = d[ i[0] ] + i[3]
        else:
            d[ i[0] ] = i[3]
    return max( d, key=d.get )

print( obterEstadoMaisViolento( lst ) )

Exit:

ARIZONA

1

Assuming you already have the data separated by state, we can define a function that sums the crime rates:

def soma_criminalidade(estado):
    return sum(cidade[3] for cidade in estado[1])

But since the data are not grouped by state, we have to group them. For this, we use the itertools.groupby:

estados = itertools.groupby(data, key=itemgetter(0))

Thus, estados will be an eternal that groups all cities for each state. To find the state with greater crime, just do:

maior_criminalidade = max(estados, key=soma_criminalidade)

That generates the result:

>>> print(maior_criminalidade)
('ARIZONA', <itertools._grouper object at 0x7fec56788128>)

Indicating that for the data presented, the state with the highest crime is Arizona.

To know the crime of all the states it would be enough to do:

for estado in estados:
    criminalidade = soma_criminalidade(estado)
    print(f'O estado {estado[0]} possui criminalidade {criminalidade}')

That would generate the result:

O estado ALABAMA possui criminalidade 744
O estado ARIZONA possui criminalidade 766

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