Create a key / values association from user-entered data

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Create a key / values association from user-entered data

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#1 by (4 votes)

3

8) Write an algorithm capable of receiving a variable amount of parameters that are associated with a key. Then print the key name and its value on the screen:

def func_varios_parametros_dic(**dicionario):
    print(dicionario)

lista_k = []
lista_v = []
x = 0

while True:
    lista_k.append(input("Informe a chave[q em ambos p/ sair]: "))
    lista_v.append(input("Informe o valor[q em ambos p/ sair]: "))
    if (lista_k[x] != 'q' and lista_v[x] != 'q'):
        func_varios_parametros_dic(**dict(zip(lista_k, lista_v)))
        x += 1
    else:
        break

It works fine, but if I for example type r in the key and 3 in , the output looks like this:

{'r': '3'}

r and r / em> , the output looks like this:

{'r': '5'}

What I want, is that it looks like this:

{'r': '3', 'r': '5'}

that is, if I type a repeated key , in this case the letter r , it is overwritten along with in> value 5 . I do not know why the key pair is not printed on the screen even though it is being repeated.

python python-3.x

asked by anonymous 22.11.2018 / 19:20

1 answer

MVC and DAO - Data Rules Adding data from the same column

score 4 · Accepted Answer

The dictionary defines an injection relationship between the keys and the values. In practice, this implies that the key of a dictionary must be unique and related to only one value (the opposite is not valid since a value can be associated with more than one key).

See official language documentation :

It is best to think of a dictionary as a set of key: value pairs, with the requirement that the keys are unique . A pair of braces creates an empty dictionary: {}. Placing a comma-separated list of key: value pairs within the braces adds initial key: value pairs to the dictionary; this is also the way dictionaries are written on output.

Therefore, the {'r': '3', 'r': '5'} output you want can not be obtained - not with standard dictionary at least. But since the statement does not require the key to be duplicated, just that it is possible to associate multiple values with a key, you can create a list to store the values.

Also, regarding your solution, I find it a bit uncomfortable for the user to have to enter the key every time they want to enter a new value. You can here define two repeat loops to read the values of each key indefinitely.

dicionario = {}

while True:
    chave = input('Entre com a chave [enter para sair]: ')
    if not chave:
        break
    if chave not in dicionario:
        dicionario[chave] = []
    while True:
        valor = input(f'Entre com o valor para a chave {chave} [enter para sair]: ')
        if not valor:
            break
        dicionario[chave].append(valor)

print('Seu dicionário final é:')
print(dicionario)

So, I would stay:

Entre com a chave [enter para sair]:  a
Entre com o valor para a chave a [enter para sair]:  1
Entre com o valor para a chave a [enter para sair]:  2
Entre com o valor para a chave a [enter para sair]:  
Entre com a chave [enter para sair]:  b
Entre com o valor para a chave b [enter para sair]:  1
Entre com o valor para a chave b [enter para sair]:  
Entre com a chave [enter para sair]:  
Seu dicionário final é:
{'a': ['1', '2'], 'b': ['1']}

You can still use some variations of the dictionary, such as collections.defaultdict . to set the default value type if it does not exist in the dictionary.

Notice that I used Enter itself to end each loop because the key / value pair {'q': 'q'} is probably perfectly valid within the dictionary.