如何检查在 Python 中使用 Walrus 运算符时是否按下了 Enter 键？

Question

我正在尝试使用 Walrus operator 获取用户的输入:=，但如果用户只输入Enter密钥 as input，则 python 脚本将终止。如何捕获此错误并确保用户不仅按下了Enter键？

有这个答案，但它不适用于海象运算符。

这段没有 walrus 运算符的代码将成功检查是否不仅Enter按下了键：

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

如果用户只按下Enter，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

您将赋值表达式放在了错误的位置。您的原始循环是无限的，但您的第二个循环用作answer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，由于我们使用的是continue，else因此不需要该子句。

行动中：

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

然而，在这里使用 walrus 运算符没有真正的优势，所以我会避免它。

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