5 months ago.

natalie.py

"""
A portmanteau word is a blend of two or more words, like 'mathelete',
which comes from 'math' and 'athelete'

rules are: a portmanteau must be composed of three non-empty pieces, 
             start+mid+end, 
        'adolescented' comes from 
        'adolescent','scented', with 
    start+mid+end='adole'+'scent'+'ed'.

score:    'adole'+'scent'+'ed', the 
start,mid,end lengths are 5,5,2 and the total length is 12.  The ideal
start,mid,end lengths are 12/4,12/2,12/4 = 3,6,3. So the final score

     12 - abs(5-3) - abs(5-6) - abs(2-3) = 8.  

A portmanteau must be composed of two different words (not the same word twice).

The output of natalie(words) should be the best portmanteau, or None """
#--------------------------------------------------------------------------


import itertools
import doctest

def natalie(words): 
    results = []
    # ['int', 'intimate', 'hinter', 'hint', 'winter']
    for w1, w2 in itertools.combinations(words,2):
        if w1 not in w2 and w2 not in w1:  
            for m in presubfixes(w1):# all possible prefix,subfixes from w1 
                if m in w2 and valid(m, w1, w2):  #invalid => ('hi' 'hint' 'hiner') 
                    results.append(three_parts(m, w1, w2))
                    break #(presub fixes are sorted by lens), when we find :'initi' not need to do 'init'
    return sorted(results) if results else None

def valid(m, w1, w2): 
    return w1.startswith(m) + w2.startswith(m) == 1


#     middle   word1     word2
# ('phant', 'elephant', 'phantom') => 'ele + phant + om'
#('int', 'intimate', 'hint') => 'h + int + imate' 

def three_parts(m, w1, w2):
    L = len(m)
    parts = ((w1[:-L], m, w2[L:]) if w2.startswith(m) else 
             (w2[:w2.index(m)], m, w1[L:]))
    if not all(parts): return # if not compose of start, mid, end
    return calculate(*parts), ''.join(parts) 

def calculate(*words):
    s, m, e = map(len, words)
    t = s + m + e
    return t - abs(s-t/4.) - abs(m-t/2.) - abs(e-t/4.)

# >>> presubfixes('kimono') 
#['kimon', 'imono', 'kimo', 'mono', 'kim', 'ono', 'no', 'ki', 'o', 'k']   

def presubfixes(w):
    mixes = [(w[i:],w[:i]) for i in range(1, len(w))] 
    return sorted([y for x in mixes for y in x], key=len)[::-1]