如何用值获取Python字典的键问题

d = {1:'a', 2:'a', 3:'b', 5:'c'}
print(d[5])

def get_keys_by_value(the_dict, the_value):
	rl = list()
	for k in the_dict.keys():
		if the_dict[k] == the_value:
			rl.append(k)
	return rl
if __name__ == "__main__":
	d = {1:'a', 2:'a', 3:'b', 8:'f'}
	print('the keys are: ', get_keys_by_value(d, 'a'))

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 获取字典中 "name" 键对应的值
value = my_dict["name"]
print(value)  # 输出：Tom　　

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 获取字典中 "name" 键对应的值
value = my_dict.get("name")
print(value)  # 输出：Tom
# 获取字典中 "phone" 键对应的值，由于 "phone" 不存在，返回 None
value = my_dict.get("phone")
print(value)  # 输出：None　　

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 获取字典中所有键值对
items = my_dict.items()
print(items)  # 输出：dict_items([('name', 'Tom'), ('age', 18), ('gender', 'male')])
# 遍历所有键值对
for key, value in items:
    print(f"{key}: {value}")

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 获取字典中所有键
keys = my_dict.keys()
print(keys)  # 输出：dict_keys(['name', 'age', 'gender'])
# 遍历所有键
for key in keys:
    value = my_dict[key]
    print(f"{key}: {value}")　　

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 获取字典中所有值
values = my_dict.values()
print(values)  # 输出：dict_values(['Tom', 18, 'male'])
# 遍历所有值
for value in values:
    print　　

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 判断 "name" 是否在字典中
if "name" in my_dict:
    print("name is in my_dict")  # 输出：name is in my_dict
# 判断 "phone" 是否在字典中
if "phone" in my_dict:
    print("phone is in my_dict")
else:
    print("phone is not in my_dict")  # 输出：phone is not in my_dict　　

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 删除字典中 "age" 键的键值对，并返回对应的值
value = my_dict.pop("age")
print(value)  # 输出：18
print(my_dict)  # 输出：{"name": "Tom", "gender": "male"}　　

# 定义一个字典
my_dict = {"name": "Tom", "age": 18, "gender": "male"}
# 删除字典中的任意一个键值对，并返回对应的键值对
key, value = my_dict.popitem()
print(key, value)  # 输出：gender male
print(my_dict)  # 输出：{"name": "Tom", "age": 18}