常见的字符串相关操作

连续空格去重

val s = "a b     c          ddd"
println(s)
println(s.replaceAll(" +", " "))

结果:
a b     c          ddd

a b c ddd

字符串插值

val name = "zhangsan"
println(s"hello ${name}")

结果: 
hello zhangsan