python重复list中元素中的字母次数

Question

例如实现以下的情况：
words = ['hello', 'exercise', 'with', 'words']
repeat_letter(words, [4, 2, 10, -2], 3)
words = ['helloooo', 'exeeeercise', 'with', 'wordddds']

Answer 1

words = ['hello', 'exercise', 'with', 'words']

def repeat_letter(words,index,num):
    return_worlds=[]
    for i in range(0,len(words)):
        if len(words[i]) > index[i]:
            word_list=list(words[i])
            range_word=word_list[index[i]]*(num+1)
            word_list[index[i]]=range_word
            new_word=''.join(word_list)
        else:
            new_word =words[i]
        return_worlds.append(new_word)
    return  return_worlds

print repeat_letter(words, [4, 2, 10, -2], 3)

# words = ['helloooo', 'exeeeercise', 'with', 'wordddds']

Answer 2

#! /usr/bin/env python3
# -*- coding: utf-8 -*-

def repeat_letter(word_list,handle_list,repeat_cycles):
    for i in range(min(len(word_list),len(handle_list))):
        words = list(word_list[i])
        if handle_list[i] < len(words):
            word = words[handle_list[i]]
            word = word*(repeat_cycles+1)
            words[handle_list[i]] = word
        word_list[i] = "".join(words)
    print (word_list)
    return word_list

Answer 3

def repeat_letter(words, positions, times):
    return list(map(lambda w,p: w[:p] + w[p:p+1]*(times+1) + w[p+1:], words, positions))

words = ['hello', 'exercise', 'with', 'words']

print(repeat_letter(words, [4, 2, 10, -2], 3))

# ['helloooo', 'exeeeercise', 'with', 'wordddds']