Formatting a numerical string w/commas

[Timothy Grant]

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<<<<<<<<<<<<