userList.add(user3); User user4 =newUser(); user4.setAge(25); userList.add(user4); doubleaverage = userList.stream().mapToInt(User::getAge).average().orElse(0.0); System.out.println("average : "+ average); } reduce的基本用法 1、初识 reduce 的基本 api 1 2 3 4 5 6 7 8 ...
Stream.of("one", "two", "three", "four").peek(e -> System.out.println(e));输出:这样不会有任何的输出;Stream.of("one", "two", "three", "four").peek(e -> System.out.println(e)).collect(Collectors.toList());输出:onetwothreefourStream.of("one", "two", "three", "four")....
value.toString():value.toString().toLowerCase();for(String pattern:patternsToSkip){line=line.replaceAll(pattern,"");}StringTokenizer itr=newStringTokenizer(line);while(itr.hasMoreTokens()){word.set(itr.nextToken());context.write(word,one);Counter counter=context.getCounter(CountersEnum.class.getN...
(IntWritable.class); List<String> otherArgs = new ArrayList<String>(); for (int i=0; i < remainingArgs.length; ++i) { if ("-skip".equals(remainingArgs[i])) { job.addCacheFile(new Path(EMapReduceOSSUtil.buildOSSCompleteUri(remainingArgs[++i], conf)).toUri()); job.getConfiguration(...
在这个NextKeyValue中调用的是Input的输入数据 return value; } catch (IOException ie) { throw new RuntimeException("next value iterator failed", ie); } catch (InterruptedException ie) { // this is bad, but we can't modify the exception list of java.util throw new RuntimeException("next ...
(false); // --- Merging Phase --- //数据合并阶段,即将磁盘上的临时文件进行归并成一个iterator // make sure we have enough memory to merge and for large record handling //读磁盘临时文件的内存缓冲区,使用的是异步IO List<MemorySegment> mergeReadMemory; if (largeRecordHandler != null && larg...
Scroll through the list of connections and look for an item that hasData Modellisted in theDescriptioncolumn. If you find it, then the workbook contains a Data Model. One good way to optimize a Data Model is to configure it to bring in only the data that you need. Here are some r...
The types of keys and values differ based on the use case. All inputs and outputs are stored in the HDFS. While the map is a mandatory step to filter and sort the initial data, the reduce function is optional. <k1, v1> -> Map() -> list(<k2, v2>)<k2, list(v2)> -> Reduce...
Hive is a data warehouse infrastructure built on top of Hadoop. It provides a series of tools that can be used to extract, transform, and load (ETL) data. Hive is a mecha
str_list= ['lilei','hmm','de8ug','debug1','de8ug2']deflh(s: str):returnre.search('de8ug', s)print(list(filter(lh, str_list))) 1.3 reduce 减少,合并 官方:Applyfunctionof two arguments cumulatively to the items ofsequence, from left to right, ...