Convert a number enclosed in parentheses (string) to a negative integer (or float) using Python?

Question

In Python, what is the simplest way to convert a number enclosed in parentheses (string) to a negative integer (or float)?

For example, '(4,301)' to -4301, as commonly encountered in accounting applications.

I don't know of a built-in way to do it. You can parse the comma-separated integer with [`locale`](http://stackoverflow.com/questions/1779288/how-do-i-use-python-to-convert-a-string-to-a-number-if-it-has-commas-in-it-as-th), but you'll need to handle the negativity yourself. — Katriel, May 23 '13 at 16:04
Strange, there is `locale.currency` to go the other way, but you want the inverse of that which I can't seem to find .. same question was asked here already and no satisfactory answers http://stackoverflow.com/q/8421922/674039 — wim, May 23 '13 at 16:16

score 13 · Accepted Answer · answered May 23 '13 at 16:04

13

The simplest way is:

my_str = "(4,301)"
num = -int(my_str.translate(None,"(),"))

answered May 23 '13 at 16:04

Crowman

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Wow, translate is awesome! – ecline6 May 23 '13 at 16:19
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Thanks, this led me to `int('(4,301)'.replace('(','-').translate(None,'), '))` which was enough for my purposes. – silvernightstar May 27 '13 at 01:14
Hi there. this answer assumes that i'm only going to deal with negative numbers. Any solution for when I'm not sure whether it'll be negative or positive ? – Pedro Braz Jan 20 '16 at 11:50
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@PedroBraz: It doesn't assume that. If there are no parentheses, it just won't translate any, and will just remove any commas. – Crowman Jan 20 '16 at 12:24
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true say, but the minus is outside the function, thus it'll be negative even though parenthesis abscense. I mean, i know a if will solve that, I was just looking for a clean solution. Thanks a lot for the answers ! – Pedro Braz Jan 20 '16 at 12:35
@PedroBraz: OK, you may have misunderstood the premise of the question, which deals with numbers presented in the accounting convention where negative numbers are shown enclosed in parentheses, and not with a minus sign. There is no "function" here - if your number has a minus sign, then you just have an incorrectly formatted number, at least in terms of the format that this question is asking about. For a number like `-4,301`, just get rid of the comma and convert it with `Int()`. – Crowman Jan 20 '16 at 12:56
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@PaulGriffiths, I think PedroBraz is pointing out that if you set my_str to '4,301', num will be set to -4301. It's clear from a comment above that this is not the behavior silvernightstar wants, and it's probably not the behavior Pedro Braz wants either (http://stackoverflow.com/questions/16718648/convert-a-number-enclosed-in-parentheses-string-to-a-negative-integer-or-floa#comment24153742_16718742). – Vectornaut May 30 '16 at 08:36
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@PedroBraz, in case you're still interested, I think silvernightstar's comment above gives the kind of clean solution you're looking for (http://stackoverflow.com/questions/16718648/convert-a-number-enclosed-in-parentheses-string-to-a-negative-integer-or-floa#comment24153742_16718742). – Vectornaut May 30 '16 at 08:37

score 8 · Answer 2 · answered May 23 '13 at 16:11

8

Since you are reading from a system that put in thousands separators, it's worth mentioning that we are not using them the same way all around the world, which is why you should consider using a locale system. Consider:

import locale
locale.setlocale( locale.LC_ALL, 'en_US.UTF-8' )
my_str = "(4,301)"
result = -locale.atoi(my_str.translate(None,"()"))

answered May 23 '13 at 16:11

mogul

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Thank you Sir. I am in Denmark, and experience all kinds of crap due to "interesting" locales... – mogul May 23 '13 at 16:15

Jon Clements · Answer 3 · 2013-05-23T16:22:46.693

Assuming just removing the , is safe enough, and you may wish to apply the same function to values that may contain negative numbers or not, then:

import re
print float(re.sub(r'^\((.*?)\)$', r'-\1', a).replace(',',''))

You could then couple that with using locale as other answers have shown, eg:

import locale, re

locale.setlocale(locale.LC_ALL, 'en_GB.UTF-8')
print locale.atof(re.sub('^\((.*?)\)$', r'-\1', a))

score 4 · Answer 4 · answered May 13 '19 at 06:22

4

For Python 3.6, and also handles '-' as 0, and strips excess empty spaces:

def clean_num(num_string):
    bad_chars = '(),-'
    translator = str.maketrans('', '', bad_chars)
    clean_digits = num_string.translate(translator).strip()

    if clean_digits == '':
        return 0
    elif '(' in num_string:
        return -float(clean_digits)
    else:
        return float(clean_digits)

answered May 13 '19 at 06:22

yl_low

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Worked for me !! we can update bad_chars with additional bad charcs to get desired result – Tokci May 27 '21 at 12:15

score 2 · Answer 5 · edited May 23 '17 at 10:30

2

Presumably you want to handle positive numbers as well as negative, which is missing from many of the answers thus far. I'm going to add a bit to the answer from mogul.

import locale
locale.setlocale( locale.LC_ALL, '')
my_str = '( 4,301 )'
positive = my_str.translate(None, '()')
result = locale.atoi(positive) if positive == my_str else -locale.atoi(positive)

edited May 23 '17 at 10:30

Community

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answered May 23 '13 at 16:40

Mark Ransom

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Julio Batista Silva · Answer 6 · 2020-04-16T15:18:38.740

2

For localized numbers, I use this:

def clean_number(text):
    import locale
    locale.setlocale(locale.LC_NUMERIC, "Portuguese_Brazil.1252")
    tbl = str.maketrans('(', '-', 'R$ )')
    return locale.atof(text.translate(tbl))

Works with Python 3.8. The first parenthesis is replaced with the minus sign, the second is removed. Also removes spaces and the monetary sign.

edited Apr 16 '20 at 15:18

answered Apr 16 '20 at 15:12

Julio Batista Silva

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score 0 · Answer 7 · answered May 23 '13 at 16:27

This code could be a little bit longer, but straight forward and easy to maintain

from pyparsing import Word, nums, OneOrMore

integer = Word(nums)

text = "blah blah (4,301) blah blah " 

parser = OneOrMore(integer)

iterator = parser.scanString( text )

try:
    while True:
        part1 =  iterator.next()
        part2 =  iterator.next()
except:
    x =  part1[0][0][0] + '.' +part2[0][0][0]
    print -float(x)

Produces: -4.301

score 0 · Answer 8 · answered Mar 08 '23 at 04:05

As of today, the top answer is specific to Python 2. I tried editing it, but the queue is full.

For my_str = "(4,301)", the top answer advises:

num = -int(my_str.translate(None,"(),"))

For Python 3, you would instead use one of the following:

translate_table = dict({ord(i): None for i in '(),'})
num = -int(my_str.translate(translate_table))

or, more simply

num = -int(my_str.translate({ord(i): None for i in "(),"}))

If you're curious, the change is necessary for two reasons:

str.translate() now expects a single argument.
The str type contains Unicode. This is why each key in the dictionary is first passed to ord: this function accepts a given Unicode character and returns the Unicode code point for it:
```
 >>> ord('(')
 40
```

Convert a number enclosed in parentheses (string) to a negative integer (or float) using Python?

8 Answers8

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