19.scala编程思想笔记——for循环
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For循环会遍历一个值序列，使用其中的每一个值执行某些操作。
有多种编写for循环的简洁方式，常用的三种表达式例如：0 to 9, 0 until 10 和 Range(0,10)
例如：
import com.atomicscala.AtomicTest._
var result = ""
for(i <- 0 to 9) {
result += i +" "
}
result is "0 1 2 3 4 5 6 7 8 9 "
result = ""
for(i <- 0 until 10) {
result += i +" "
}
result is "0 1 2 3 4 5 6 7 8 9 "
result = ""
for(i <- Range(0, 10)) {
result += i +" "
}
result is "0 1 2 3 4 5 6 7 8 9 "
result = ""
for(i <- Range(0, 20, 2)) {
result += i +" "
}
result is "0 2 4 6 8 10 12 14 16 18 "
var sum = 0
for(i <- Range(0, 20, 2)) {
println("adding " + i + " to " + sum)
sum += i
}
sum is 90
执行如下：
0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9
0 2 4 6 8 10 12 14 16 18
adding 0 to 0
adding 2 to 0
adding 4 to 2
adding 6 to 6
adding 8 to 12
adding 10 to 20
adding 12 to 30
adding 14 to 42
adding 16 to 56
adding 18 to 72
90
