y:Int)=>x+y //add是一个函数add: (Int, Int) => Intadd(4,5) //采用数学界的括号调用样式res2: Int = 9add.apply(4,5) //add也是对象，采用点号形式调用apply方法res3: Int = 9函数是对象，反过来，对象也可以看成函数。当然，前提是该对象提供了apply方法3、update方法和un
2.需求:创建一个RDD(由字符串组成),过滤出一个新RDD(包含"xiao"子串) 1) 创建 scala> var sourceFilter = sc.parallelize(Array("xiaoming...2.需求:创建一个pairRDD,将相同key对应值聚合到一个sequence中,并计算相同key对应值的相加结果。...:26 2)将相同key对应值聚合到一个sequence中 scala> val gr...
Scala中的immutable Collection 集合 Traversable 遍历 Iterable 迭代 Set无序集合 Sequence序列 Map映射 Set...,表明一个转换过程,参数中的匿名函数参数x是List中得每个元素 //使用map实现全部字母大写 scala> c.map(x => x.toUpperCase) res23: List[String]...filter和map来实现对List中过滤后元素的具体操作 ...
Anorm parameter can be multi-value, like a sequence of string.In such case, values will be prepared to be passed to JDBC.// With default formatting (", " as separator) SQL("SELECT * FROM Test WHERE cat IN ({categories})"). on('categories -> Seq("a", "b", "c") // -> ...
Likewise, q_* or q_s can be used to extract a sequence of multi valued query parameters:val router = Router.from { case GET(p"/items" ? q_s"tag=$tags") => Action { val allTags = tags.mkString(", ") Results.Ok(s"Showing items tagged: $allTags") } }Multiple query parameters ...
36 CharSequence subSequence(int beginIndex, int endIndex)返回一个新的字符序列,它是此序列的一个子序列 37 String substring(int beginIndex)返回一个新的字符串,它是此字符串的一个子字符串 38 String substring(int beginIndex, int endIndex)返回一个新字符串,它是此字符串的一个子字符串 39 char[] toCh...
(1, 2) // same thing for (_ <- 1 to 10) // same thing f(xs: _*) // Sequence xs is passed as multiple parameters to f(ys: T*) case Seq(xs @ _*) // Identifier xs is bound to the whole matched sequence var i: Int = _ // Initialization to the default value def abc_...
sequence是一种线性元素的集合,可能会是索引或者线性的(链表)。map是包含键值对的集合,就像Java的Map,set是包含无重复元素的集合。 除了这三个主要的集合类之外,还有其他有用的集合类型,如Stack, Queue和Range。还有其他一些用起来像集合的类,如元组、枚举、Option/Some/None以及Try/Success/Failure类。
Double2double any2stringadd exceptionWrapper readByte unwrapString DummyImplicit any2stringfmt fallbackStringCanBuildFrom readChar wrapBooleanArray Ensuring arrayToCharSequence float2Float readDouble wrapByteArray Float2float assert floatArrayOps readFloat wrapCharArray ...
- Scala For Beginners This book provides astep-by-stepguide for thecomplete beginnerto learn Scala. It is particularly useful to programmers, data scientists, big data engineers, students, or just about anyone who wants toget up to speed fastwith Scala (especially within an enterprise context)...