gistfile1.py

import itertools

# Utilities
# Using curried form

# Split an iterable at a point where some given predicate is met
split_at = lambda f: lambda l: \
    (itertools.takewhile(lambda e: not f(e), l), itertools.dropwhile(lambda e: not f(e), l))

# Append an element to a list
append = lambda l: lambda e: l + [e]

# Map a pair of functions over a pair of values, pairwise (heh)
map_pair = lambda ((f, g)): lambda ((a, b)): (f(a), g(b))

# Uncurry. To turn a curried function into an uncurried one
uncurry = lambda f: lambda ((a, b)): f(a)(b)

# The actual function
# Ideally the 'list' application should be 'id (lambda v: v)', but somehow that
# drops a single element from every range except for the first or the last, not
# sure why :-/
group_ranges = lambda ranges: lambda values: \
    uncurry(append)(
        reduce(
            lambda (acc, vs), d: map_pair((append(acc), list))(split_at(lambda e: e >= d)(vs)),
            ranges,
            ([], sorted(values))))

# Demo
test_data = range(0, 15)
test_ranges = [2, 5, 9]
# Think ranges = [(0, 2), (2, 5), (5, 9)]

print map(list, group_ranges(test_ranges)(test_data))