Decimal zero padding

I need to output decimal numbers in a price forma开发者_如何学编程t,

i.e.

10 = 10.00 11.1 = 11.10

How can I achieve this using decimal.Decimal class ?

pad_zero(Decimal('10.0'))
>>>Decimal('10.00')

*EDIT:*format method does not fit my need because I need to pass it on as decimal, I understand though, that i can convert it back to afterwards, but such to-and-fro seems somewhat unpythonic.

---

try this :

Decimal('10.0').quantize(Decimal('1.00'))

---

For currency calculations, I prefer this.

>>> penny=Decimal('0.01')
>>> Decimal('10').quantize(penny)
Decimal('10.00')

It's wordy but explicit.

For currency formatting, I use format().

---

There's a good example of how to format Decimal objects as a "money formatted string" in the Python documentation for the decimal module.

I'm a little surprised at how awkward it is -- usually formatting in Python is fairly straightforward.

---

I would follow the moneyfmt recipe in the Python Decimal documentation Recipes section.

This recipe creates a function that takes a decimal value and returns a string formatted as a currency.

>>> d = Decimal('10.0')
>>> moneyfmt(d, curr='$')
'$10.00'

Below is the actual code, copied sans examples from the Decimal Recipe documentation:

def moneyfmt(value, places=2, curr='', sep=',', dp='.',
             pos='', neg='-', trailneg=''):
    """Convert Decimal to a money formatted string.

    places:  required number of places after the decimal point
    curr:    optional currency symbol before the sign (may be blank)
    sep:     optional grouping separator (comma, period, space, or blank)
    dp:      decimal point indicator (comma or period)
             only specify as blank when places is zero
    pos:     optional sign for positive numbers: '+', space or blank
    neg:     optional sign for negative numbers: '-', '(', space or blank
    trailneg:optional trailing minus indicator:  '-', ')', space or blank

    """
    q = Decimal(10) ** -places      # 2 places --> '0.01'
    sign, digits, exp = value.quantize(q).as_tuple()
    result = []
    digits = map(str, digits)
    build, next = result.append, digits.pop
    if sign:
        build(trailneg)
    for i in range(places):
        build(next() if digits else '0')
    build(dp)
    if not digits:
        build('0')
    i = 0
    while digits:
        build(next())
        i += 1
        if i == 3 and digits:
            i = 0
            build(sep)
    build(curr)
    build(neg if sign else pos)
    return ''.join(reversed(result))

---

It should be quite simple like this (if you don't use decimal.Decimal class as suggested by S. Lott) :

    >>> decimal_fmt = "{:.2f}"   
    >>> x = 10
    >>> print(decimal_fmt.format(x))
    10.00
    >>> x = 11.1
    >>> print(decimal_fmt.format(x))
    11.10

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Set the precision for your context before you create your instance:

>>> getcontext().prec = 2

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Use locale currency. It works flawlessly with the Decimal class.

import locale
locale.setlocale(locale.LC_ALL, '') # this sets locale to the current Operating System value
print(locale.currency(Decimal('1346896.67544'), grouping=True, symbol=True))

will output in my Windows 10 configured to Brazilian Portuguese:

R$ 1.346.896,68

It is somewhat verbose, so if you will use it a lot, maybe it is better to predefine some parameters and have a shorter name and use it inside a f-string:

fmt = lambda x: locale.currency(x, grouping=True, symbol=True)
print(f"Value: {fmt(1346896.67444)}"

It works with Decimal and float. You can configure to symbol to False if it isn't necessary.

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Instead of using Decimal('10.0') you could use float('10.0') which will produce the effect you require.

Edit: Realised that you were looking to represent it with 2 decimal places. In this case, there's a good example in the Python docs for converting a Decimal() object to money: http://docs.python.org/library/decimal.html#recipes