java flatmap

Map: For the elements contained in the stream, the newly generated stream contains only the elements that are generated by the transformation, using the given conversion function. This method has three variant methods for the original type, namely Maptoint,maptolong and maptodouble. These three methods are also better understood, for example Maptoint is to convert the original stream into a new stream, and the elements in the newly generated stream are of type int. There are three variants that

ObjectiveSwift is actually much more complex than objective-c, and Swift incorporates a number of new features compared to Objective-c, born in the 80 's. It also makes it more difficult for us to learn to master the language. But everything is worth it, Swift compared to Objective-c, the program written out more safe, more concise, and ultimately improve our efficiency and quality.There are a lot of Swift-related learning materials, and I want to introduce some of its features from another pers

This paper describes the three most common operations map, FLATMAP, filter, and the relationship of the for expression in collections.The implementation of list on three kinds of methodsMap in the implementation of list:abstractclass List[+T] { defthismatch { case x :: xs => f(x) :: xs.map(f) case Nil => Nil }}The implementation of FLATMAP in list:abstractclass List[+T] { defthismatch { case x :

) res6:list[string] = List (Kraps, Poodah, Esabh)Flatmap function:The "FlatMap" function has half the same function as the map function, but there is a requirement that the returned value of the incoming function be a list (should be seq) after processing, and if the result is not a list (seq), an error occurs. In other words, the function passed in is required-the return value is a SEQ line. Thus, after ea

Today we will learn how to use the for expression to implement map, Flatmap, and filterFirst, let's look at the map. The function of map is to pass in a list, through a function f, to change the element A in list to the process of element B. Finally get the list formed by B. If this process is implemented by a For loop, the following actions are performed:for (element Next we look at the Flatmap. The functi

Map () is the function used for each element in the RDD, and the return value constitutes a new rdd. Flatmap () is to apply a function to each element in the RDD, and to make all the contents of the returned iterator a new rdd, so that an RDD consists of elements from each list, rather than a list of rdd. A bit of a mouthful, look at the examples to understand. Val Rdd = sc.parallelize (List ("Coffee Panda", "Happy Panda", "Happiest Panda Party")) In

For security, performance, and so on, most servers will have some interfaces that need to pass tokens to return the results correctly, and token needs to be fetched from another interface, which requires two successive requests to get the data (①token->② target data).Using FlatMap () enables this continuous request with clearer code, avoiding Callback nested structures. Code approximate formApi.gettoken (). FlatMa