Python Config Parser (Duplicate Key Support)

Question

So I recently started writing a config parser for a Python project I\'m working on. I initially avoided configparser and configobj, because I wanted to support a config file

Answer 1

Crazy idea: make your dictionary values as a list of 3-tuples with line number, col number and value itself and add special key for comment.

CommentSymbol = ';'
def readConfig(filename):
    f = open(filename, 'r')
    if not f:
        return
    def addValue(dict, key, lineIdx, colIdx, value):
        if key in dict:
            dict[key].append((lineIdx, colIdx, value))
        else:
            dict[key] = [(lineIdx, colIdx, value)]
    res = {}
    i = 0
    for line in f.readlines():
        idx = line.find(CommentSymbol)
        if idx != -1:
            comment = line[idx + 1:]
            addValue(res, CommentSymbol, i, idx, comment)
            line = line[:idx]
        pair = [x.strip() for x in line.split('=')][:2]
        if len(pair) == 2:
            addValue(res, pair[0], i, 0, pair[1])
        i += 1
    return res

def writeConfig(dict, filename):
    f = open(filename, 'w')
    if not f:
        return
    index = sorted(dict.iteritems(), cmp = lambda x, y: cmp(x[1][:2], y[1][:2]))
    i = 0
    for k, V in index:
        for v in V:
            if v[0] > i:
                f.write('\n' * (v[0] - i - 1))
            if k == CommentSymbol:
                f.write('{0}{1}'.format(CommentSymbol, str(v[2])))
            else:
                f.write('{0} = {1}'.format(str(k), str(v[2])))
            i = v[0]
    f.close()