Question

我有一系列价格是字符串，看起来像这样＆＃34; $ 100.00＆＃34;。我想检查所有这些价格的总和，但在我需要将String更改为数字之前，我这样做了：

val price2 = "$100.00"
val price3 = "INCLUDED"
val price4 = "$200.00"
val prices: Array<String> = arrayOf(price2, price3, price4)

这里是我如何将String更改为Float：

 for (s: String in prices) {
            //I replace all dollar signs to empty space
            val s1 = s.replace("$", "")
            //I replace Included price to 0
            val s2 = s1.replace("INCLUDED", "0")
            //Change type to float
            val p = s2.toFloat()
            println(p)
        }

如何找到所有这些变化元素的总和？我的意思是，我希望总和为100.0 + 0.0 + 200.0。我试过的事情：

//added this into for loop  
val sum = +p
println(sum)

或者

 //I tried to put this into the loop and after it
 val x = prices[0] + prices[1] + prices[2]
 println(x)

感谢您的帮助！我一直试图在Kotlin写作，但Java示例会很好。

编辑：我一直在考虑将p添加到新阵列中然后找到第二阵列的总和，但我不知道如何做到这一点。

Answer 1

试试这个：

var sum = 0
for (s: String in prices) {
        //I replace all dollar signs to empty space
        val s1 = s.replace("$", "")
        //I replace Included price to 0
        val s2 = s1.replace("INCLUDED", "0")
        //Change type to float
        val p = s2.toFloat()
        println(p)
        sum += p // NO var keyword!
}
println(sum)

Answer 2

更实际的解决方案：

val prices = listOf(price2, price3, price4)
val pricesParsed = prices.map {it.replace("$", "")}.map {it.toFloatOrNull() ?: 0f}
println(pricesParsed.sum())

Answer 3

也可以这样做：

var p:Float = 0.0f
for(i :String in prices) {
   var s1 =   i.replace("$","")
   var s2 = s1.replace("INCLUDED","0")
   p  = p + s2.toFloat()
}

Kotlin \ Java - 如何获取已更改的数组元素的总和

3 个答案: