如何提示用户输入，直到输入在Julia中有效

我试图制作一个程序来提示用户输入，直到他们输入特定范围内的数字

---

当我输入超出指定范围的字母、符号或数字时，确保代码不会出错的最佳方法是什么

这是实现这类目标的一种可能方式：

while true
    print("Please enter a whole number between 1 and 5: ")
    input = readline(stdin)
    try
        if parse(Int, input) <= 5 || parse(Int, input) >= 1
            print("You entered $(input)")
            break
        end
    catch
        @warn "Enter a whole number between 1 and 5"
    end
end

作为替代，您可以使用：

tryparse（type，str；base）

与解析类似，但返回请求类型的值，或

nothing

如果字符串不包含有效数字

与parse相比，它的优点是，您可以在不诉诸于的情况下进行更干净的错误处理，这将隐藏块中引发的所有异常

例如，您可以执行以下操作：

while true
    print("Please enter a whole number between 1 and 5: ")
    input = readline(stdin)
    value = tryparse(Int, input)
    if value !== nothing && 1 <= value <= 5
        println("You entered $(input)")
        break
    else
        @warn "Enter a whole number between 1 and 5"
    end
end

---

令人惊叹的！谢谢你指出这一点。如果您认为它看起来更简单，请随时发布替代解决方案。

while true
    print("Please enter a whole number between 1 and 5: ")
    input = readline(stdin)
    value = tryparse(Int, input)
    if value !== nothing && 1 <= value <= 5
        println("You entered $(input)")
        break
    else
        @warn "Enter a whole number between 1 and 5"
    end
end

Please enter a whole number between 1 and 5: 42
┌ Warning: Enter a whole number between 1 and 5
└ @ Main myscript.jl:9
Please enter a whole number between 1 and 5: abcde
┌ Warning: Enter a whole number between 1 and 5
└ @ Main myscript.jl:9
Please enter a whole number between 1 and 5: 3
You entered 3