Programming Paradigm -- Functional

functional.py

# Functional
def normalize_state(s):
    return s.strip().lower().replace(’.’,’’)

def mean(nums):
    return sum(nums) / len(nums)

def extract_state_age(l):
    pieces = l.split(’,’)
    return normalize_state(state), float(age)

def get_state_mean(pairs):
    ages_by_state = {}
    for age, state in pairs:
        ages_by_state[state] = ages_by_state.setdefault(state,[]) + [age]

    state_mean_pairs = [(state, mean(ages)) for state, ages in ages_by_state.items()]

    return sorted(state_mean_pairs, key=lambda p: p[1])

def format_output(state_age_pairs):
    out_lines = [state + ’,’ + str(age) for state, age in state_age_pairs]

    return '\n'.join(out_lines)

lines = open('data.txt')
state_age_pairs = [extract_state_age(l) for l in lines]
output = format_output(state_age_pairs)
open('output.txt','w').write(output)