Formatting a numerical string w/commas

[bjorn]

The only problem with these kinds of approaches, is that you are trying to
reimplement locale dependent formatting by hand (and most approaches assume
everyone is using the us locale :-)

-- bjorn
ps: as far as the coding style, the only suggestion I have would be to put
the function comment in a doc string...

Timothy Grant wrote:

> I've seen some traffic on this formatting numbers, and recently had to
> format and deformat some number for a Tkinter app I was writing, so I
> wrote to fairly generic functions for doing so.
>
> This is the first time I've ever posted *real* code on the list so
> please be gentle, but constructive criticism, especially about style, is
> always welcome.
>
> ############################################################
> #
> # Name: commanumber()
> #
> # Purpose:  To format a number with commas and possibly a
> #           dollar sign.
> #
> # Arguments:    n  = the number to be converted
> #               dp = number of decimal places (defaults to 2)
> #               ds = dollar sign (1|0) (defaults to $)
> #
> def commanumber(n, dp=2, ds=1):
>
>     if not n:
>         return ''       # If None then bail out here
>
>     if type(n) == type('x'):
>         if n == '':
>             return ''   # If an empty string then bail out here.
>         n = string.atof(n)
>
>     m = '%0.*f' % (dp, n)
>
>     d = string.split(m, '.')    # Split at the decimal point
>     r = list(d[0])
>
>     # It looks ugly but it really isn't. A couple of really nice
> Pythonisms
>     # make it work right. The first is list insertion, and the second is
> integer
>     # division.
>     #
>     # the insertion point is calculated based on the counter item, plus
> the a left
>     # shift for each ',' already inserted the ((x/3)-1)
>     #
>     for x in range(3, len(r), 3):
>         r[(x+((x/3)-1))*(-1):(x+((x/3)-1))*(-1)] = [',']
>
>     if ds:
>         s = '$'
>     else:
>         s = ''          # Rebuild the string from the list
>
>     for i in r:
>         s = s + i
>
>     if len(d) == 2: # Check to see if we have a decimal portion to add
>         return s + '.' + d[1]
>     else:
>         return s
>
>
> ############################################################
> #
> # Name: stripfmt()
> #
> # Purpose:  Strip all formatting from a prettified number
> #
> # Arguments:    n = the number to strip
> #
> def stripfmt(n):
>     n = string.replace(n, ',', '')  #remove commas
>     n = string.replace(n, '$', '')  #remove dollar signs.
>     return n
>
> --
> Stand Fast,
>     tjg.
>
> Chief Technology Officer              tjg at exceptionalminds.com
> Red Hat Certified Engineer            www.exceptionalminds.com
> Avalon Technology Group, Inc.                   (503) 246-3630
> >>>>>>>>>>>>Linux...Because rebooting isn't normal<<<<<<<<<<<<
>
> --
> http://www.python.org/mailman/listinfo/python-list