如何解决Python中的IndexError: list index out of range错误？

错误原因 #

你遇到的IndexError: list index out of range是循环边界处理错误导致的：

• word是"redf"，长度为4，word_list的有效索引范围是0到3（列表索引从0开始）。
• 你的while循环条件是num_of_letters >= times_looped，当times_looped等于4时仍会进入循环，此时访问word_list[4]超出了列表的索引范围，触发错误。
• 内部的if条件times_looped <= num_of_letters也存在同样的边界问题。

修复后的代码 #

调整循环边界，同时简化元素替换逻辑（无需pop和insert，直接赋值更高效）：

dictionary = {"a": 1, "b": 2, "c": 3, "d": 4, "e": 5, "f": 6, "g": 7, "h": 8, "i": 9, "j": 10, "k": 11, "l": 12, "m": 13, "n": 14, "o": 15, "p": 16, "q": 17, "r":18}

word = "redf"
word_list = list(word)

num_of_letters = len(word)
times_looped = 0

# 仅遍历有效索引范围
while times_looped < num_of_letters:
    replacement_num = dictionary.get(word_list[times_looped])
    word_list[times_looped] = replacement_num
    times_looped += 1
    print(word_list)

更简洁的写法 #

用列表推导式可以一步完成转换，代码更简洁易读：

dictionary = {"a": 1, "b": 2, "c": 3, "d": 4, "e": 5, "f": 6, "g": 7, "h": 8, "i": 9, "j": 10, "k": 11, "l": 12, "m": 13, "n": 14, "o": 15, "p": 16, "q": 17, "r":18}

word = "redf"
word_list = [dictionary.get(char) for char in word]
print(word_list)

内容的提问来源于stack exchange，提问作者sirpixelz