gistfile1.txt

def subs2(expr, substitutions):
    """
    extends subs to conveniently support arrays
    subs2(['a', [3,4]]) becomes subs([('a_0', 3), ('a_1', 4)])
    """
    subslist = []
    for name, val in substitutions:
        if hasattr(val, '__getitem__') and not isinstance(val, str):
            for i, vali in enumerate(val):
                indexedname = '{}_{}'.format(name, i)
                subslist.append((indexedname, vali))
        else:
            subslist.append((name, val))
    return expr.subs(subslist)