Java中多个集合中的子串计数

Question

我在番石榴多个集合中有以下数据。每一项都是由“：”分隔的三个项的组合字符串。我知道每个插槽的所有值。我使用这些值为交互式图形生成数据文件(通过将拆分的值填充到对象中，然后使用Gson打印对象)。

获取所有仅匹配1、1:2或1:2:3子串的所有项的累积计数的最佳方法是什么？我不停地使用流、forEach、映射和过滤器，但似乎无法编写一组优雅的循环。任何建议或例子都是有帮助的。

行政主管:医疗保健:美国x5

行政主管:医疗保健:马来西亚x2

执行:财务:美国x1

金融健康:技术:马来西亚x3

财务健康:技术:美国x2

财政健康:能源:美国x1

行政=8

FinancialHealth =6

行政人员:卫生保健=7

执行人员:财务=1

财务健康:技术=5

财政健康:能源=1

行政主管:医疗保健:美国=5

等。

Answer 1

溪流在这里有很大的帮助，而且也不困难。我们需要在一条小溪里走三步：

allTheStrings.stream()
                  // First, we will multiply each string "A:B:C" using `flatMap`
                  // so that the stream contains "A", "A:B", and "A:B:C":
             .flatMap(s -> Stream.of(s.substring(0, s.indexOf(":")),
                                     s.substring(0, s.lastIndexOf(":")),
                                     s))
                  // next, we are going to summarize multiple occurrences
                  // of the strings using a groupingBy collector:
             .collect(Collectors.groupingBy(Function.identity(),
                 // This would return a Map<String, List<String>> containing each unique
                 // string mapped to its occurrences. But because you don't need the
                 // single occurrences, but instead just their number, we add a step
                 // to the collect which will make it return a Map<String, Long>
                                            Collectors.counting()))

因此，作为一个完整的例子：

Stream.of("Executive:Healthcare:United States", "Executive:Healthcare:United States",
          "Executive:Healthcare:United States", "Executive:Healthcare:United States",
          "Executive:Healthcare:United States", "Executive:Healthcare:Malaysia",
          "Executive:Healthcare:Malaysia", "Executive:Financials:United States",
          "FinancialHealth:Technology:Malaysia", "FinancialHealth:Technology:Malaysia",
          "FinancialHealth:Technology:Malaysia", "FinancialHealth:Technology:United States",
          "FinancialHealth:Technology:United States", "FinancialHealth:Energy:United States")
      .flatMap(s -> Stream.of(s.substring(0, s.indexOf(":")), s.substring(0, s.lastIndexOf(":")), s))
      .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()))
      .entrySet()
      .forEach(System.out::println);

威尔输出

Executive=8
Executive:Healthcare=7
FinancialHealth:Technology=5
FinancialHealth=6
FinancialHealth:Energy=1
FinancialHealth:Technology:Malaysia=3
FinancialHealth:Energy:United States=1
Executive:Healthcare:United States=5
Executive:Financials:United States=1
FinancialHealth:Technology:United States=2
Executive:Healthcare:Malaysia=2
Executive:Financials=1