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fp2023:lab06 [2023/04/04 13:33] pdmatei |
fp2023:lab06 [2023/04/10 10:53] (current) pdmatei |
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| The function ''groupBy'' takes a list with elements of type ''A'', a criterion ''A => B'' and produces a list of pairs ''(c, lp) : (B,List[A])'' with the property that each member of the list ''lp'' satisfy the criterion with the value ''c''. Suppose ''f: A => B'' is a criterion. Two elements ''a : A'' and ''b : A'' satisfy the criterion ''f'' **iff** ''f(a) == f(b)''. Examples: | The function ''groupBy'' takes a list with elements of type ''A'', a criterion ''A => B'' and produces a list of pairs ''(c, lp) : (B,List[A])'' with the property that each member of the list ''lp'' satisfy the criterion with the value ''c''. Suppose ''f: A => B'' is a criterion. Two elements ''a : A'' and ''b : A'' satisfy the criterion ''f'' **iff** ''f(a) == f(b)''. Examples: | ||
| <code> | <code> | ||
| - | groupBy(List("john", "mary", "bill"))(_.size) = List((2,List("john","mary")), (1, List("bill"))) | + | groupBy(List("john", "mary", "mihai"))(_.size) = List((4,List("john","mary")), (5, List("mihai"))) |
| - | groupBy(List((1,2), (2,1), (3,3))(p => p._1 + p._2) = List((3,List((1,2),(2,1)), (6, List((3,3))) | + | groupBy(List((1,2), (2,1), (3,3))(p => p._1 + p._2) = List((3,List((1,2),(2,1))), (6, List((3,3))) |
| </code> | </code> | ||
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| **6.2.3.** Write a function which checks is there exist identical names under different domains in a list of emails (e.g. ''ana@amazon.com'' and ''ana@gmail.com'') | **6.2.3.** Write a function which checks is there exist identical names under different domains in a list of emails (e.g. ''ana@amazon.com'' and ''ana@gmail.com'') | ||
| <code scala> | <code scala> | ||
| - | def containsDuplicates(l: List[Email]): List[Email] = ??? | + | def containsDuplicates(l: List[Email]): Boolean = ??? |
| </code> | </code> | ||
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| </code> | </code> | ||
| - | **6.2.5.** Write a function which reports **all duplicates** of names under different domains in a list of emails. (e.g. ''["ana@aol.com", "ana@aol.ro", "jim@cx.com", "mary@mail.com" , "mary@mail.ro"]'' will produce: ''[["ana@aol.com", "ana@aol.ro"], ["mary@mail.com" , "mary@mail.ro"]]'' | + | **6.2.5.** Write a function which reports **all duplicates** of names under different domains in a list of emails. (e.g. ''["ana@aol.com", "ana@aol.ro", "jim@cx.com", "mary@mail.com" , "mary@mail.ro"]'' will produce: ''[ ["ana@aol.com", "ana@aol.ro"], ["mary@mail.com" , "mary@mail.ro"]]'' |
| <code scala> | <code scala> | ||
| def extractDuplicates(l: List[Email]): List[List[Email]] = ??? | def extractDuplicates(l: List[Email]): List[List[Email]] = ??? | ||
| </code> | </code> | ||
| - | **6.2.6.** Write a function which removes **all duplicates** of names under different domains in a list of emails. (e.g. ''["ana@aol.com", "ana@aol.ro", "jim@cx.com", "mary@mail.com" , "mary@mail.ro"]'' will produce: ''[["ana@aol.com", "ana@aol.ro"], ["mary@mail.com" , "mary@mail.ro"]]'' | + | **6.2.6.** Write a function which removes **all duplicates** of names under different domains in a list of emails. (e.g. ''["ana@aol.com", "ana@aol.ro", "jim@cx.com", "mary@mail.com" , "mary@mail.ro"]'' will produce: ''[ ["ana@aol.com", "ana@aol.ro"], ["mary@mail.com" , "mary@mail.ro"]]'' |
| <code scala> | <code scala> | ||
| def extractDuplicates(l: List[Email]): List[List[Email]] = ??? | def extractDuplicates(l: List[Email]): List[List[Email]] = ??? | ||