Python：将列表添加到现有字典中吗？

Question

I have a dictionary with an int as value for each key. I also have total stored in a variable. I want to obtain a percentage that each value represent for the variable and return the percentage to the dictionary as another value for the same key.

I tried to extract the values in a list, then do the operation and append the results to another list. But I don't know how to append that list to the dictionary.

total = 1000

d = {"key_1":150, "key_2":350, "key_3":500}

lst = list(d.values())

percentages = [100 * (i/total) for i in lst]


# Desired dictionary

d

{"key_1": [15%, 150],

"key_2": [35%, 350],

"key_3": [50%, 500]
}

Answer 1

You're better off avoiding the intermediate list and just updating each key as you go:

total = 1000

d = {"key_1":150, "key_2":350, "key_3":500}

for k, v in d.items():
    d[k] = [100 * (v / total), v]

While it's technically possible to zip the dict 's keys with the values of the list , as long as the keys aren't changed and the list order is kept in line with the values extracted from the dict , the resulting code would reek of code smell, and it's just easier to avoid that list entirely anyway.

Note that this won't put a % sign in the representation, because there is no such thing as a percentage type. The only simple way to shove one in there would be to store it as a string, not a float , eg replacing the final line with:

    d[k] = [f'{100 * (v / total)}%', v]

to format the calculation as a string, and shove a % on the end.

Answer 2

Here

total = 1000
d = {"key_1": 150, "key_2": 350, "key_3": 500}
d1 = {k: ['{}%'.format(v * 100 / 1000),v] for k, v in d.items()}
print(d1)

output

{'key_1': ['15.0%', 150], 'key_2': ['35.0%', 350], 'key_3': ['50.0%', 500]}