Scala <控制台>：1：错误：';' 预期但 '(' 发现
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Scala <console>:1: error: ';' expected but '(' found
提问by Anas
I keep getting this error when writing a simple recursive function in Scala. What am I missing?
在 Scala 中编写简单的递归函数时，我不断收到此错误。我错过了什么？
scala> def count(n1:Int, n1:Int) : List[Int] = (n1 < n2) ? List() : List(n1, count((n1 - 1), n2))
<console>:1: error: ';' expected but '(' found.
def count(n1:Int, n1:Int) : List[Int] = (n1 < n2) ? List() : List(n1, count((n1 - 1), n2))
回答by Brian
In Scala the ternary operator is if. So, ?and :can be replaced with the usual ifand elsekeywords.
在 Scala 中，三元运算符是if。所以，?and:可以替换为常用的if和else关键字。
Also, where is n2defined? I'll guess in countlike this def count(n1:Int, n2:Int) : List[Int] = ...
另外，在哪里n2定义？我想在count这样的def count(n1:Int, n2:Int) : List[Int] = ...
回答by korefn
This works!
这有效！
def count(n1:Int, n2:Int) : List[Int] = if (n1 < n2) List() else n1 :: count((n1 - 1), n2))
def count(n1:Int, n2:Int) : List[Int] = if (n1 < n2) List() else n1 :: count((n1 - 1), n2))
change count(n1:Int, n1:Int)to count(n1:Int,n2)The rest is adding an if elseclause instead of the ternary oprator.
更改count(n1:Int, n1:Int)为count(n1:Int,n2)其余的是添加一个if else子句而不是三元运算符。
A similar code for doing this would be def count(n1:Int, n2:Int) = (n1 to n2).reverse
执行此操作的类似代码是 def count(n1:Int, n2:Int) = (n1 to n2).reverse
