python: how to convert currency to decimal?

Question

i have dollars in a string variable

dollars = '$5.99'

how do i convert this to a decimal instead of a string so that i can do operations with it like adding dollars to it?

Answer 1

If you'd prefer just an integer number of cents:

cents_int = int(round(float(dollars.strip('$'))*100))

If you want a Decimal, just use...

from decimal import Decimal
dollars_dec = Decimal(dollars.strip('$'))

If you know that the dollar sign will always be there, you could use dollars[1:] instead of dollars.strip('$'), but using strip() lets you also handle strings that omit the dollar sign (5.99 instead of $5.99).

Answer 2

Assuming the string stored in the variable dollars was generated using python's locale module. A potentially cleaner way to convert it back to float (decimal) is to use the atof function from the same module. It should work as long as you use the same setlocale parameters in both directions (from currency to string and vice-versa).

for instance:

import locale
locale.setlocale(locale.LC_ALL, '')
value = 122445.56
value_s = locale.currency(value, grouping=True)
#generates $122,445.56

to convert it back:

value2 = locale.atof(value_s[1:])
#value2 = 122445.56 
value == value2 #True

Answer 3

There's an easy approach:

dollar_dec = float(dollars[1:])

Answer 4

I know this an old question, but this is a very simple approach to your problem that's easily readable:

for:

dollars = '$5.99'
dollars = dollars.replace("$","").replace(",","")
/* 5.99 */

It also works with a larger number that might have a comma in it:

dollars = '1,425,232.99'
dollars = dollars.replace("$","").replace(",","")
/* 1425232.99 */

Answer 5

If you want to use Decimal:

from decimal import Decimal
dollars = Decimal(dollars.strip('$'))

From there adding is pretty simple

dollars += 1 # Would add 1 to your decimal

Answer 6

Through decimal package

>>> dollars = '$5.99'
>>> import decimal
>>> decimal.Decimal(dollars[1:])
Decimal('5.99')
>>> 

Answer 7

If you are only going to be adding (and not multiplying or dividing) consider just storing cents instead of dollars and not using the decimal package. I suggest using the simplest tool for the job, and decimal doesn't provide any value if you are just adding dollars and cents.

Answer 8

First, strip off the '$' character. If it's always consistently the first character, that's easy:

dollars[1:]

To keep the cents perfect without worrying about the non-perfect representation of cents in floating point, you'll want to use Decimal values:

from decimal import *
Decimal(dollars[1:])

Answer 9

If you want to keep moneys in cents for easy rounding and sometimes '$' is missing:

for dollars in ('$5.99','6.77'):
    cents = int(float((dollars[1:] if dollars.startswith('$') else dollars))*100)
    print '%s = %i cents = %i dollars and %i cents' % ((dollars, cents)+divmod(cents, 100))

Answer 10

Here's another example of converting a messy currency string into a decimal rounded down to the cent:

from decimal import Decimal, ROUND_DOWN

messy = ',   $1, 111.2199  ,,,'

less_messy = Decimal(''.join(messy.replace(',','').split()).replace('$',''))
converted = less_messy.quantize(Decimal(".01"), rounding=ROUND_DOWN)

print(converted)
1111.21

Other rounding options include: ROUND_HALF_UP, ROUND_HALF_DOWN, ROUND_UP