如何在字典或字典中查找字符串是键还是值

def find_string_in_dict(dictionary, target_string):
    if target_string in dictionary:
        return "键"
    for value in dictionary.values():
        if target_string == value:
            return "值"
    return "既不是键也不是值"

# 示例
my_dict = {'apple': '苹果', 'banana': '香蕉', 'cherry': '樱桃'}
target = '苹果'
print(find_string_in_dict(my_dict, target))  # 输出: 值

def check_string_in_dict(dictionary, target_string):
    is_key = target_string in dictionary
    is_value = any(target_string == value for value in dictionary.values())
    if is_key and not is_value:
        return "键"
    elif not is_key and is_value:
        return "值"
    elif is_key and is_value:
        return "既是键也是值"
    else:
        return "既不是键也不是值"

# 示例
my_dict = {'apple': '苹果', 'banana': '香蕉', 'chberos': '樱桃'}
target = '苹果'
print(check_string_in_dict(my_dict, target))  # 输出: 值

def find_string_case_insensitive(dictionary, target_string):
    target_string = target_string.lower()
    for key, value in dictionary.items():
        if key.lower() == target_string:
            return "键"
        if value.lower() == target_string:
            return "值"
    return "既不是键也不是值"