Kotlin學習筆記(25) 檢查字串是數字 ?

Kotlin學習筆記(25) 檢查字串是數字 ? 
源自於 https://www.programiz.com/kotlin-programming/examples/check-string-numeric

val string = "-1234.15"
var numeric = true

fun main(args: Array<String>) {
    numeric = string.matches("-?\\d+(\\.\\d+)?".toRegex())
    if (numeric)
        println("$string is a number")
    else
        println("$string is not a number")
}

輸出畫面
-1234.15 is a number

In the matches() method,

• -? allows zero or more - for negative numbers in the string.
• \\d+ checks the string must have atleast 1 or more numbers (\\d).
• (\\.\\d+)? allows zero or more of the given pattern (\\.\\d+) in which
  • \\. checks if the string contains . (decimal points) or not
  • If yes, it should be followed by at least one or more number \\d+.

Here's the equivalent Java code: Java program to check if a string is numeric or n