changeling

Changeling2

from WordLookup import lookup

# This is a helper function which converts a word string into a list with each letter as an element
def wordToList(word):
    i=0
    a=[]
    while i < len(word):
        a.append(word[i])
        i+=1
    return a

# This is a helper function which converts a list of letters into one word as a string
def ListToStr(Llist):
    a=''
    i=0
    while i < len(Llist):
        b=Llist[i]
        i+=1
        a=a+b
    return a

# This helper function takes a word as parameter and returns the list of words that are only one letter different from the word
def oneLetterDiff(word):
    letterlist=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']
    resultlist=[]
    wordlist=wordToList(word)
    for i in range (len(wordlist)):
        for letter in letterlist:        
            if wordlist[i]!=letter:
                newWord=wordlist
                newWord[i]= letter
                newWordstr=ListToStr(newWord)
                wordlist=wordToList(word)
                if lookup(newWordstr) != False:
                    resultlist.append(newWordstr)
    return resultlist

# This is the main function which allows as to solve the changeling puzzle with a recursive function, the result gives a list from the starting word going through each steps to the final desired word
processList=[]
def changeling (start,end,steps):
    global processList
    processList.append (start)
    if lookup (start) == False or lookup(end) == False:
        return None
    if start.islower()== False or end.islower()==False:
        return None
    if steps < 0:
        return None
    if len(start)!= len(end):
        return None
    if steps == 0 and start==end:
        return end
    elif steps == 0 and start !=end:
        return None
    else:
        wordList=oneLetterDiff(start)
        for n in wordList:
            if n in processList:
                continue
            else:
                start=n 
            changeling(start,end,steps-1)
            return processList