4、Scala与Clojure：函数式编程的魅力与实践

Scala与Clojure：函数式编程的魅力与实践

1. Scala中的函数值与多参数列表

在Scala编程中，函数值的使用十分灵活。我们可以通过以下代码来计算价格总和：

println("Total of prices is " +
totalPrices(prices, { price => true }))
//Total of prices is 227
println("Total of prices over 40 is " +
totalPrices(prices, { price => price > 40 }))
//Total of prices over 40 is 127
println("Total of prices under 40 is " +
totalPrices(prices, { price => price < 40 }))
//Total of prices under 40 is 100

这里，我们将集合和函数值作为参数传递给 totalPrices 函数。在Scala里，还支持多参数列表的函数定义，例如：

def totalPrices(
prices : List[Int])(selector : Int => Boolean) = {
prices.foldLeft(0) { (total, price) =>
if (selector(price)) total + price else total