Rebrickable API tool to find colour replacements

colourswap.py

#!/usr/bin/env python

# Finds colour replacements for an LDraw file.

# Usage:

# colourswap.py <LDraw file> <colour> [<rarity>]

# colour: an LDraw colour number, eg yellow = 14
# rarity: pieces must be in at least this many sets

import urllib2
import json
import sys

api_key = "rebrickable API key goes here"

try:
    minimum_rarity = int(sys.argv[3])
except:
    minimum_rarity = 1

def get_colours(part):
    response = urllib2.urlopen('https://rebrickable.com/api/v3/lego/parts/' + part + '/colors/?key=' + api_key)
    data = json.load(response)
    colours = set()
    for item in data['results']:
        if item['num_sets'] > minimum_rarity:
            colours.add(item['color_name'])
    return colours

parts = set()
colours = []

if __name__ == '__main__':
    with open(sys.argv[1]) as data:
        for line in data:
            x = line.strip().split()
            if x[0] == '1':
                colour = x[1]
                if colour == sys.argv[2]:
                    part = x[-1][:-4]
                    parts.add(part)

    for part in parts:
        colours.append(get_colours(part))

    print 'Parts:'
    print ', '.join(parts)
    print 'Common Colours:'
    print ', '.join(set.intersection(*colours))