Decimal list to float list in dictionary

Question

I have list from mssql query which includes Decimals. Such as:

 [(1, Decimal('33.00'), Decimal('5.30'), Decimal('50.00')),
  (2, Decimal('17.00'), Decimal('0.50'), Decimal('10.00'))]

I want to transform that to dict and float number like that:

 {1: [33.00, 5.30, 50.00],
  2: [17.00, 0.50, 10.00]}

I writed below line:

load_dict = {key: values for key, *values in dataRead}

which results:

{1: [Decimal('33.00'), Decimal('105.30'), Decimal('25650.00')],
 2: [Decimal('17.00'), Decimal('40.50'), Decimal('10000.00')]}

I am asking that is there anyway making this transformation with list/dict comprehension?

score 3 · Answer 1 · answered Oct 24 '18 at 14:55

3

you could use a dict-comprehension with a cast to float like this:

from decimal import Decimal

lst = [(1, Decimal('33.00'), Decimal('5.30'), Decimal('50.00')),
  (2, Decimal('17.00'), Decimal('0.50'), Decimal('10.00'))]

ret = {key: [float(f) for f in values] for key, *values in lst}
print(ret)
# {1: [33.0, 5.3, 50.0], 2: [17.0, 0.5, 10.0]}

answered Oct 24 '18 at 14:55

hiro protagonist

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Your way is also simple but daniel answer not use "for loop". Therefore it seems more compact. Thanks for your answer. – kur ag Oct 24 '18 at 15:00
3

List comprehensions with `for` are generally preferred over `map` these days. – John Kugelman Oct 24 '18 at 15:04
@JohnKugelman Is there significant performance difference? And If you add reference, I can look. – kur ag Oct 24 '18 at 15:23
1

See: [Python List Comprehension Vs. Map](https://stackoverflow.com/questions/1247486/python-list-comprehension-vs-map) – John Kugelman Oct 24 '18 at 16:09

Dani Mesejo · Accepted Answer · 2018-10-24T14:56:37.167

1

Apply float to values:

from decimal import Decimal

data = [(1, Decimal('33.00'), Decimal('5.30'), Decimal('50.00')),
  (2, Decimal('17.00'), Decimal('0.50'), Decimal('10.00'))]

load_dict = {key: list(map(float, values))  for key, *values in data}

print(load_dict)

Output

{1: [33.0, 5.3, 50.0], 2: [17.0, 0.5, 10.0]}

edited Oct 24 '18 at 14:56

answered Oct 24 '18 at 14:54

Dani Mesejo

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Decimal list to float list in dictionary

2 Answers2