Example 2: Check if a string is numeric or not using regular expressions (regex) fun main(args: Array<String>) { val string = "-1234.15" var numeric = true numeric = string.matches("-?\\d+(\\.\\d+)?".toRegex()) if (numeric) println("$string is a number") else println("$...
When working with numbers, we often encounter scenarios where we must check whether a given number is positive or negative. In this tutorial, we’ll explore how to effectively check if a number is positive or negative in Kotlin. Further, we’ll build step by step an idiomatic function that ...
filter(numberRegex::matches) //sampleEnd fun main(args: Array<String>) { println("Result is $numbers") } 更详细信息请参阅其 KEEP。 密封类和数据类 Kotlin 1.1 删除了一些对 Kotlin 1.0 中已存在的密封类和数据类的限制。 现在你可以在同一个文件中的任何地方定义一个密封类的子类,而不只是以作为...
1. Overview In this tutorial, we’ll see a simple solution for a classic programming challenge: deciding if a number is even (divisible by 2) or odd (non-divisible by 2). We’ll see how therem()operator works in Kotlin, and see samples of how we can use it to check a number’s...
在Java中,复合按钮CompoundButton的勾选状态有两个,setChecked和isChecked,前者用于设置是否勾选,后者用于判断是否勾选,但在Kotlin中这两个方法被统一成了isChecked属性,修改isChecked的属性即为设置是否勾选,而获取isChecked的属性值即为判断是否勾选,这种合二为一的情况还有一些,如下表: ...
private var name:String?=null 1. 定义不可为空变量 private var age = "18" 1. 从这里好像看不出来有什么不同,接下来我们分别获取他们的长度: //定义可为空变量 val nameLength = name?.length val nameLength02 =name?.length?:0 val nameLength01 = name!!.length ...
is String -> "it is String." is Number -> "it is Number" else -> "it is not String or Number." } } // 逻辑表达式模式(注意,这种模式下,when后没有跟变量名) ``` fun logicPattern(a: Int) = when { a in 2..11 -> "${a} in [2,11]." ...
importcom.jetbrains.demo1funmain(args:Array<String>){demo1()} 然后运行次程序您会看到控制台输出 demo1 kotlin会默认导入一些包,这些包您无需在上方通过import手动导入 kotlin.* kotlin.annotation.* kotlin.collections.* kotlin.comparisons.*
android kotlin 判断 any 是否为 String kotlin类型推断 基本类型 https:///huanglizhuo/kotlin-in-chinese/blob/master/Basics/Basic-Types.md 在Kotlin 中,所有变量的成员方法和属性都是一个对象。一些类型是内建的,它们的实现是优化过的,但对用户来说它们就像普通的类一样。在这节中,我们将会讲到大多数的类型...
This article explores different ways to check if a String is numeric in Kotlin... The toDouble() function parses the string as a Double number and returns the result.