如何检查在Python中使用Walrus操作符时是否按下了Enter键？

Question

我试图使用Walrus操作符:=从用户那里获取输入，但是如果用户只键入输入键作为input，python脚本将终止。如何捕获此错误并确保用户没有只按了回车键

有this answer，但使用walrus操作符无法工作

不带walrus操作员的该代码将成功检查是否仅按下了Enter键：

while True:
    answer = input("Please enter something: ")
    if answer == "":
        print("Invalid! Enter key was pressed.")
        continue
    else:
        print("Enter wasn't pressed!")
        # do something

如果用户只按Enter键，则整个脚本将终止

while answer := input("Please enter something: "):
    # if user pressed only `Enter` script will terminate. following will never run
    if answer == "":
        print("enter was pressed")
    else:
        print("Enter wasn't pressed!")
        # do something

Answer 1

你把赋值表达式放错地方了。原始循环是无限的，但第二个循环使用answer作为中断条件

while True:
    if not (answer := input("Type something: ")):
        print("You didn't type anything before pressing Enter!")
        continue
    print("You typed:", answer)

同样，因为我们使用的是continue，所以不需要else子句

在行动中：

Type something: hello!
You typed: hello!
Type something:
You didn't type anything before pressing Enter!
Type something: hi!
You typed: hi!

然而，在这里使用walrus操作符并没有真正的优势，所以我会避免使用它

while True:
    answer = input("Type something: ")
    if not answer:
        print("You didn't type anything before pressing Enter!")
        continue
    print("You typed:", answer)