题解 | 字典新增

eng_dic = {
    "a": ["apple", "abandon", "ant"],
    "b": ["banana", "bee", "become"],
    "c": ["cat", "come"],
    "d": "down",
}
letter = input()
word = input()


def add_word(letter, word):
    for k, v in eng_dic.items():
        if letter in k:
            if len(v) == 1:
                v = [v, word]
                print(v)
            else:
                v.append(word)
            return eng_dic
        else:
            eng_dic[letter] = word
            return eng_dic


print(add_word(letter, word))

根据示例可以看到字典格式为：

• 当 value 数量为 1 时，value 以单个字符的形式保存
• 当 value 数量为 2 时，value 以数组的方式保存