Dictionary Coding in Python

sentence=input("Enter your TEXT: ")

words = sentence.split()
uniqueWords=[]
codedWords=[]

print("")


def checkUnique(uniqueWords,word):
    position=0
    while True:
        if uniqueWords[position]==word:
            #print("Coded word found in position",position,)
            codedWords.append(position)
            break
        else:
            #print("fail")
            position=position+1




position=0
for word in words:
    if word in uniqueWords:
        #print("NOT UNIQUE")
        checkUnique(uniqueWords,word)



    else:
        #print("UNIQUE")
        uniqueWords.append(word)
        codedWords.append(position)
        position=position+1


print("====================================================")


print("")
print(words)
print("")
print(uniqueWords)
print("")
print(codedWords)