如何在Kotlin中将String转换为Int?

问题描述：

我正在Kotlin上的控制台应用程序上工作，在那里我在main()函数中接受多个参数

I am working on a console application in Kotlin where I accept multiple arguments in main() function

fun main(args: Array<String>) {
    // validation & String to Integer conversion
}

我想检查String是否为有效整数并将其转换为整数，否则我必须抛出一些异常.

I want to check whether the String is a valid integer and convert the same or else I have to throw some exception.

我该如何解决?

答

您可以在String实例上调用toInt():

fun main(args: Array<String>) {
    for (str in args) {
        try {
            val parsedInt = str.toInt()
            println("The parsed int is $parsedInt")
        } catch (nfe: NumberFormatException) {
            // not a valid int
        }
    }
}

或toIntOrNull()作为替代:

for (str in args) {
    val parsedInt = str.toIntOrNull()
    if (parsedInt != null) {
        println("The parsed int is $parsedInt")
    } else {
        // not a valid int
    }
}

如果您不关心无效值，则可以将toIntOrNull()与安全调用运算符和作用域函数结合使用，例如:

If you don't care about the invalid values, then you could combine toIntOrNull() with the safe call operator and a scope function, for example:

for (str in args) {
    str.toIntOrNull()?.let {
        println("The parsed int is $it")
    }
}

如何在Kotlin中将String转换为Int?

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