Mapping Letters to the numbers they are associated with on a telephone.

gistfile1.py

tarting_value = [0, 0] + [3 for i in range(5)] + [4, 3, 4]
partial_sums = [sum(starting_value[:i]) for i in range(len(starting_value)+1)]

letter_to_number = dict(reduce(
    lambda x,
    y: x+y,
    [map(lambda letter: (letter, number), letters) for number, letters in enumerate(map(lambda a_list: map(lambda char: chr(char+65), a_list), [range(*value) for value in zip(partial_sums[:-1], partial_sums[1:])]))]
))


letter_to_number = dict((letter, number) for number, letters in enumerate(map(lambda a_list: map(lambda char: chr(char+65), a_list), [range(*value) for value in zip(partial_sums[:-1], partial_sums[1:])])) for letter in letters)

-- OR --

current_number = 0
ranges_for_number = {}
for number, number_letters in enumerate(starting_value):
    ranges_for_number[number] = (current_number, current_number+number_letters)
    current_number += number_letters

letter_to_number = {}
for number, letters in enumerate(map(lambda a_list: map(lambda char: chr(char+65), a_list), [range(*value) for value in ranges_for_number.itervalues()])):
    for letter in letters:
        letter_to_number[letter] = number