如何在条件语句中获取项的值?

Question

如何在条件语句中获取字典项的值，例如

names = {"one":"john", "two":"justin"}
prompt = input("enter option: ")
if prompt == names["one"]:
print("hey, I am here")

你会建议我使用类似于第3行的解决方案，以便我如果用户输入一个键，例如"one"它打印"john">

Answer 1

in

---

在Python中存在一个名为in的关键字，它有几种使用方式。例如:

>>> 'i' in "in"
True

.keys()和。values()

---

字典内置类有两个方法:keys()和values()。
它们是这样使用的:

>>> Dictionary = {"one":"john", "two":"justin"}
>>> Dictionary.keys()
["one", "two"]
>>> Dictionary.values()
["john", "justin"]

它们也是可下标的，因为它们返回列表

<标题>

---

你可以这样做:

names = {"one":"john", "two":"justin"}
prompt = input("enter name: ")
if prompt in names.values():
print("Hey, I'm here")

<标题>编辑

---

这应该可以工作:

# According to PEP-8 you should always leave a space after ':' in a dict
names = {"one": "john", "two": "justin"}
prompt = input("enter number: ")
if prompt in names.keys():
print(f"Hey, {names[prompt]} is here!")

Answer 2

你可以试试in

names = {"one":"john", "two":"justin"}
prompt = input("enter name: ")
if prompt in names.values():
print("hey, I am here")