将字典的 python 值从列表转换为浮点数

Question

I usually program in another language but need python for something currently. I would like to convert the strings from this python dictionary to floats, but the tips I've read online aren't working exactly as I'd hoped.

example= dict({'Baker': '16,765',
 'Benton': '93,590',
 'Clackamas': '419,425',
 'Clatsop': '39,200',
 'Columbia': '51,900',
 'Coos': '63,275'})

The following results in only taking the first integer

for key in example.keys():
    example[key] = [float(example[key][0]),float(example[key][1])]
example

Out[]: 
{'Baker': [1.0, 6.0],
 'Benton': [9.0, 3.0],
 'Clackamas': [4.0, 1.0],
 'Clatsop': [3.0, 9.0],
 'Columbia': [5.0, 1.0],
 'Coos': [6.0, 3.0]}

And the following is still a string

{k:(map(float, example[k])) for k in example}
example

Out[]: 
{'Baker': '16,765',
 'Benton': '93,590',
 'Clackamas': '419,425',
 'Clatsop': '39,200',
 'Columbia': '51,900',
 'Coos': '63,275'}

I'm hoping you can help. I'm using python3. Thanks.

Answer 1

You've made a few mistakes. Using curly brackes, keys and values already defines a dict . You don't need to call dict() again. Then you either use dict comprehension, or the map function, but you don't need both. Lastly, you have to replace the comma with a dot to make the conversion work.

example = {
    'Baker': '16,765',
    'Benton': '93,590',
    'Clackamas': '419,425',
    'Clatsop': '39,200',
    'Columbia': '51,900',
    'Coos': '63,275'
}

in_float = {k: float(i.replace(',', '.')) for k, i in example.items()}
print(in_float)

Answer 2

If you just want the int values instead of a string, you just need this:

example = {'Baker': '16,765',
 'Benton': '93,590',
 'Clackamas': '419,425',
 'Clatsop': '39,200',
 'Columbia': '51,900',
 'Coos': '63,275'}

for key in example:
    s = example[key]
    example[key] = [int(item) for item in s.split(',')]

print(example)

Output:

{'Baker': [16, 765], 
'Benton': [93, 590], 
'Clackamas': [419, 425], 
'Clatsop': [39, 200], 
'Columbia': [51, 900], 
'Coos': [63, 275]}

Alternatively: [float(item) for item in s.split(',')] would make each value a float .

Answer 3

You can do this with a nifty one-liner:

example = {
    'Baker': '16,765',
    'Benton': '93,590',
    'Clackamas': '419,425',
    'Clatsop': '39,200',
    'Columbia': '51,900',
    'Coos': '63,275'
}

new_dict = {k: [float(i) for i in v.split(',')]
            for k, v in example.items()}

# pretty print the output
from pprint import pprint
pprint(new_dict)

Answer 4

Thanks for the answers.

This helped me realize that my main problem was the commas in the numbers. I was able to remove the commas at the source with example.replace(',','',regex=True)

And then I was able to change the data type

convert_dict = {'column_name': int}
dataframe = dataframe.astype(convert_dict)