decimal comma - Printable Version

decimal comma - Printable Version

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decimal comma - DPaul - Feb-18-2022

Hi , I need to convert "5,8" to a float = 5.8
Reading on this subject proposes 3 solutions
- Adapt the locale
- Do a replace (',','.') (if no 1000 separators)
- Regex...
I wonder if in the latest python releases something better has been proposed,
or what would be the preferred solution?
thx,
Paul

RE: decimal comma - Larz60+ - Feb-18-2022

try:

>>> x = "5,8"
>>> print(float(x.replace(',', '.')))
5.8

RE: decimal comma - DPaul - Feb-19-2022

OK Larz, that is the on I chose as well.
The only replace caveat is when there are also 1000 "." separators in the number. (like "100.000,55")
Then you have to do a merry-go-round execise in 2 or 3 steps.
thx,
Paul

RE: decimal comma - Gribouillis - Feb-19-2022

You could use str.translate()

>>> s = "100.123.654,90"
>>> s.translate({ord('.'): ',', ord(','): '.'})
'100,123,654.90'

>>> table = {ord('.'): '', ord(','): '.'}
>>> s = "100.123.654,90"
>>> s.translate(table)
'100123654.90'

RE: decimal comma - DPaul - Feb-19-2022

Translate function: nice!
If I wanted to keep a 1000 separator:

s1 = "100.123,90"
trad = {44:46,46:95}
x = s1.translate(trad)
print(x)

Output:
100_123.90

But now I'm in trouble, because python will do

print(int('100_000') + int('100_000'))

but it won't do:

print(int(x) + int('100_000'))

=> ValueError: invalid literal for int() with base 10: '100_123.90'
Any obvious rea

RE: decimal comma - DPaul - Feb-19-2022

Translate function: nice!
If I wanted to keep a 1000 separator:

s1 = "100.123,90"
trad = {44:46,46:95}
x = s1.translate(trad)
print(x)

Output:
100_123.90

But now I'm in trouble, because python will do

print(int('100_000') + int('100_000'))

but it won't do:

print(int(x) + int('100_000'))

=> ValueError: invalid literal for int() with base 10: '100_123.90'
any obvious reason why?
Paul

RE: decimal comma - bowlofred - Feb-19-2022

int is for integers only. No decimals. Perhaps you meant float()

>>> float('100_000.2')
100000.2

RE: decimal comma - Gribouillis - Feb-19-2022

You can also use the higher level function maketrans() to build the table.

>>> table = str.maketrans(',', '.', '.')
>>> s = "100.123.654,90"
>>> s.translate(table)
'100123654.90'
>>> x = float(s.translate(table)) # compose with float !
>>> x
100123654.9

RE: decimal comma - DPaul - Feb-19-2022

OK, understood.
Allowed : int(100.55)
Allowed : int('100')
Not allowed : int('100.55')
Allowed: float('100.55')
thx,
Paul

RE: decimal comma - DeaD_EyE - Feb-22-2022

It looks like i18n/l10n stuff. You can use locale to delocalize language-specific strings.

import locale

# get current systems locale
# and set it for the current running interpreter
locale.setlocale(locale.LC_ALL, locale.getlocale())

# input str from somewhere
value_str = "1.200.500,33"

# delocalize the value
# converting the resulting str into a float
value_float = float(locale.delocalize(value))

# format a float to a str with the current currency
value_currency = locale.currency(value_float)

The package babel has additional helper functions: https://babel.pocoo.org/en/latest/numbers.html