行]，InferedR]EN解决了这个问题，在编写Flink scala应用程序时做了以下更改，它有一组不同的导入。
我们可以重写MapFunction或RichMapFunction来自定义map函数,RichMapFunction的定义为:RichMapFunction[IN, OUT],其内部有一个map虚函数,我们需要对这个虚函数重写。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 val dataStream:DataStream[Int]=senv.fromElements(1,2,-3,0,5,-9,8)// 继承RichMapFunction...
// 使用FlatMapFunction实现过滤逻辑,只对字符串长度大于 limit 的内容进行切词classWordSplitFlatMap(limit:Int)extendsFlatMapFunction[String,String]{override defflatMap(value:String,out:Collector[String]):Unit={// split返回一个Array// 将Array中的每个元素使用Collector.collect收集起来,起到将列表展平的效果...
As with other Scala collections, flatMap flattens the collections returned by the mapping function into a single, flat one. As before, Map::flatMap comes in two flavors, as the mapping function can either return a single element or a pair: def flatMap[K2, V2](f: ((K, V)) => Iter...
Scala map中下划线_._2的含义 查询了相关资料后,并做了基本测试,确认.map(_._2)的含义如下 map(_._n)表示任意元组tuple对象,后面的数字n表示取第几个数.(n>=1的整数) val p=List((“hello”,35,1.50),(“nihao”,36,1.78)) res9: List[(String, Int, Double)] = List((hello,35,1.5), (...
IN_WORD};struct timeval begin, end;#ifdef TIMINGunsigned int library_time = 0;#endif/** mystrcmp()* Comparison function to compare 2 words*/int mystrcmp(const void *s1, const void *s2){return strcmp((const char *)s1, (const char *) s2);}/** mykeyvalcmp()* Comparison function ...
map(function, iterable) 其中,function 参数表示要传入一个函数,其可以是内置函数、自定义函数或者 lambda 匿名函数;iterable 表示一个或多个可迭代对象,可以是列表、字符串等。 map() 函数的功能是对可迭代对象中的每个元素,都调用指定的函数,并返回一个 map 对象。
scala中,一切类的基类为 Any 第一种: AnyRef,是Any的子类,是所有的引用类型的基类,所有的继承都来自AnyRef 第二种: AnyVal,是Any的子类,Byte\Char\Short\int\Long\Float\Double(无包装类)-->七种数据类型,Unit(无返回值类型)\Boolean 条件表达式
def map[R: TypeInformation](coMapper: CoMapFunction[IN1, IN2, R]): DataStream[R] Perform mapping operation, which is similar to map and flatMap operation in a ConnectedStreams, on elements. After the operation, the type of the new DataStreams is string. ...
As we can see, themap()method takes the functionsplit(”“)as a parameter and applies it to every element in the RDD. The result of the transformation is then returned as a new collection. It still contains two elements like the original, but the element content is the result of running...