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![extractor object
unapply : Input => Optional[Output]
case class is lucky](https://image.slidesharecdn.com/scala-the-good-parts-160115093250/85/Scala-the-good-parts-22-320.jpg)
![Partial Function Tip
scala> val m = Map(1->2, 2->3)
m: scala.collection.immutable.Map[Int,Int] = Map(1 -> 2, 2 -> 3)
scala> m.collect({case (k, v) if k % 2 ==0 => (k,v) })
res7: scala.collection.immutable.Map[Int,Int] = Map(2 -> 3)
scala> m collect {case (k, v) if k % 2 ==0 => (k,v) }
res7: scala.collection.immutable.Map[Int,Int] = Map(2 -> 3)](https://image.slidesharecdn.com/scala-the-good-parts-160115093250/85/Scala-the-good-parts-31-320.jpg)
![what a route looks like
[Http Method] [path] [controller method]
GET / controllers.Application.main
POST / controllers.Application.index
# Map static resources from the /public folder to the /assets URL path
GET /assets/*file controllers.Assets.at(path="/public", file)
GET /webjars/*file controllers.WebJarAssets.at(file)](https://image.slidesharecdn.com/scala-the-good-parts-160115093250/85/Scala-the-good-parts-54-320.jpg)
Uploaded byFuqiang Wang
Scala the-good-parts
This document summarizes some of the good parts of the Scala language based on feedback from Java developers who have used Scala. It highlights features like type inference, expression syntax everywhere, case classes, pattern matching, functions, the ecosystem including REPL, libraries, frameworks and tools, concurrency with actors, and the strengths of the type system. It also provides some warnings about using features like implicits and annotations wisely.
More Related Content
Scala the-good-parts
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- 4. –the guys whocame from Java to Scala said “ (I will never turn back to Java any more)”
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- 9. var retVal =for{ a <- numList if a != 3; if a < 8 }yield a for( a <- retVal){ println( "Value of a: " + a ); } val delimiter = if(defaultDelimiter)’;’ else ‘-’; Noreturn any more!
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- 11. Flexible Parameters But notfriendly to Javaers
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- 13. How you doit in Java Way?
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- 15. Library can help CommonsLang Google Guava Lombok
- 16. Let’s do itin Scala Way!
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- 19. special `apply` incompanion object
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- 21. Pattern Matching TakesThem All
- 22. extractor object unapply :Input => Optional[Output] case class is lucky
- 23. monad and containerobjects
- 24. monad and containerobjects you have met Option, right? But it’s more than Some or None!
- 25. Monad is tooacademic, let’s know it in an easy way import scala.collection._Go and Explore…
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- 28. Partial Applied functions AreNOT Partial Functions
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- 31. Partial Function Tip scala>val m = Map(1->2, 2->3) m: scala.collection.immutable.Map[Int,Int] = Map(1 -> 2, 2 -> 3) scala> m.collect({case (k, v) if k % 2 ==0 => (k,v) }) res7: scala.collection.immutable.Map[Int,Int] = Map(2 -> 3) scala> m collect {case (k, v) if k % 2 ==0 => (k,v) } res7: scala.collection.immutable.Map[Int,Int] = Map(2 -> 3)
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- 33. high-order Functions Try Function asreturn value
- 34. How about Java8? BothCool~ as long as you like
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- 38. What comes intoyour mind when u hear the Java word?
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- 42. Wonderful Plugins SBT NativePackager Plugin sbt-assembly sbt-dependency-graph you favoured IDEs’ Plugins
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- 44. SIP14 Rocks -Futures and Promises Composable !
- 45. SIP14 Rocks -Futures and Promises
- 46. Actor Model Don’t besilly
- 47. A Best PracticeOf Message Passing Concurrency
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- 53. route - thecentral hub
- 54. what a routelooks like [Http Method] [path] [controller method] GET / controllers.Application.main POST / controllers.Application.index # Map static resources from the /public folder to the /assets URL path GET /assets/*file controllers.Assets.at(path="/public", file) GET /webjars/*file controllers.WebJarAssets.at(file)
- 55. Perfect For WebAPIScenarios
- 56. Breakingout of WebContainers
- 57. make a killingwith big data
- 58. do you know DryadLINQ MicrosoftdoesNOT always suck
- 59. from single frameworkto family
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- 61. You know ScalaCollections well, you play with Spark well ；） val textFile = spark.textFile("hdfs://...") val errors = textFile.filter(line => line.contains("ERROR")) errors.count() errors.filter(line => line.contains("MySQL")).count() errors.filter(line => line.contains("MySQL")).collect()
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- 63. ImmediatelyVS. Wait amoment
- 64. – who saidthat?! “Where the fucking awesome type system of scala?”
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- 67. Find your owntoolbox not ONLY a Hammer
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- 69. string interpolation wisely @seealso org.slf4j.helpers.MessageFormatter
- 70. About Implicit 1. 如果有普遍的共识 和约定的，可以使用； 2. 否则，不建议使用！
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- 72. No Perfect AnnotationSolution UglyThing macross
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