python 3 compatible .dae rounding script

round_collada_numbers.py

#! /usr/bin/env python

'''
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'''
# Author: Dave Coleman
# Desc:   Rounds all the numbers to <decimal places> places

from lxml import etree
import shlex
import sys
import io

def doRound(values,decimal_places):
    num_vector = shlex.split(values)
    new_vector = []

    for num in num_vector:
        new_num = round(float(num),decimal_places)
        print("Old:",num,"New:",new_num)
        new_vector.append(str(new_num))

    new = " ".join(new_vector)
    # print 'Original:', values, '  Updated: ', new

    return new

# -----------------------------------------------------------------------------

if __name__ == '__main__':

    # Check input arguments
    try:
        input_file = sys.argv[1]
        output_file = sys.argv[2]
        decimal_places = int(sys.argv[3])
        assert( len(sys.argv) < 5 )   # invalid num-arguments
    except:
        print('\nUsage: round_collada_numbers.py <input_dae> <output_dae> <decimal places>')
        print('Rounds all the numbers to <decimal places> places\n')
        sys.exit(-1)

    print('\nCollada Number Rounder')
    print('Rounding numbers to', decimal_places, ' decimal places\n')

    # Read string from file
    f = open(input_file,'rb')
    xml = f.read();

    # Parse XML
    #doc = etree.fromstring(xml)
    #print(doc.tag)
    #doc = etree.parse(io.BytesIO(xml))
    #element=doc.xpath('//ns:asset',namespaces={'ns','http://www.collada.org/2008/03/COLLADASchema'})
    #print element

    namespace = 'http://www.collada.org/2008/03/COLLADASchema'
    dom = etree.parse(io.BytesIO(xml))

    # find elements of particular name
    elements=dom.xpath('//ns:translate',namespaces={'ns':namespace})
    for i in range(len(elements)):
        elements[i].text = doRound(elements[i].text,decimal_places)

    # find elements of particular name
    elements=dom.xpath('//ns:rotate',namespaces={'ns':namespace})
    for i in range(len(elements)):
        elements[i].text = doRound(elements[i].text,decimal_places)

    # find elements of particular name
    elements=dom.xpath('//ns:min',namespaces={'ns':namespace})
    for i in range(len(elements)):
        elements[i].text = doRound(elements[i].text,decimal_places)

    # find elements of particular name
    elements=dom.xpath('//ns:max',namespaces={'ns':namespace})
    for i in range(len(elements)):
        elements[i].text = doRound(elements[i].text,decimal_places)

    # find elements of particular name
    elements=dom.xpath('//ns:float',namespaces={'ns':namespace})
    for i in range(len(elements)):
        elements[i].text = doRound(elements[i].text,decimal_places)

    # save changes
    f = open(output_file,'wb')
    f.write(etree.tostring(dom))
    f.close()