If you are starting at Scala, and are accustomed to older languages, you may be tempted to sort a list like so:<\/p>\n
\nval x = new List(3, 1, 2)\n\nx.sortWith( \n (a, b) => { \n return a > b\n } \n)\n<\/pre>\nThis code will throw the following error:<\/p>\n
\nerror: return outside method definition\n<\/pre>\nThe intent of this code is to create the equivalent of a Java comparator, using an anonymous function. However, “return” is not defined correctly in Scala, and should never be used. <\/p>\n
The above example can be rewritten like so:<\/p>\n
\nval x = new List(3, 1, 2)\n\nx.sortWith( \n (a, b) => { \n a > b\n } \n)\n<\/pre>\nThis implicitly returns a value from the function. The “return” keyword returns from a function that is tied to an object (a “method”), so if this code was inside a method it would “work”, but drop several stack frames.<\/p>\n","protected":false},"excerpt":{"rendered":"
If you are starting at Scala, and are accustomed to older languages, you may be tempted to sort a list like so: val x = new List(3, 1, 2) x.sortWith( (a, b) => { return a > b } ) This code will throw the following error: error: return outside method definition The intent of … <\/p>\n