[英]How can I sort a Map through the keyset?
I wanted to sort a Map through its keyset elements in a growing way. 我想以不断增长的方式通过其键集元素对地图进行排序。 The join type is innerJoin.
联接类型为innerJoin。 I have this code:
我有以下代码:
Comparator<Tuple2<String, Integer>> comparator = Comparator.comparing((Function<Tuple2<String, Integer>, String>) Tuple2::get0).thenComparing(Tuple2::get1);
Map<Tuple2<String, Integer>, LongSummaryStatistics> grouped = join.stream()
.collect(groupingBy(t -> Tuples.of(t.get1().getCNation(), t.get4().getDYear()), () -> new TreeMap<>(comparator), summarizingLong(t->t.get0().getLoRevenue()-t.get0().getLoSupplycost())));
grouped.forEach((k, v) -> {
System.out.format("%-32s, %,d%n", k, v.getSum());
});
That returns this result: 返回结果:
Tuple2Impl {ARGENTINA, 1992} , 9.671.947.837
Tuple2Impl {ARGENTINA, 1993} , 10.047.205.160
Tuple2Impl {ARGENTINA, 1994} , 10.141.821.441
Tuple2Impl {BRAZIL, 1992} , 9.241.877.689
Tuple2Impl {BRAZIL, 1993} , 9.057.962.411
Tuple2Impl {BRAZIL, 1994} , 9.303.902.867
Tuple2Impl {CANADA, 1992} , 9.746.312.266
Tuple2Impl {CANADA, 1993} , 9.754.277.048
Tuple2Impl {CANADA, 1994} , 10.069.331.565
...
And I wanted to get this result: 我想得到以下结果:
Tuple2Impl {ARGENTINA, 1992} , 9.671.947.837
Tuple2Impl {BRAZIL, 1992} , 9.241.877.689
Tuple2Impl {CANADA, 1992} , 9.746.312.266
Tuple2Impl {ARGENTINA, 1993} , 10.047.205.160
Tuple2Impl {BRAZIL, 1993} , 9.057.962.411
Tuple2Impl {CANADA, 1993} , 9.754.277.048
Tuple2Impl {ARGENTINA, 1994} , 10.141.821.441
Tuple2Impl {BRAZIL, 1994} , 9.303.902.867
Tuple2Impl {CANADA, 1994} , 10.069.331.565
...
It is looks like you want to order by year then nation. 看来您想按年份再按国家订购。
Comparator<Tuple2<String, Integer>> comparator =
Comparator.comparing((Function<Tuple2<String, Integer>, Integer>) Tuple2::get1)
.thenComparing(Tuple2::get0);
EDIT Note that I use get1
then get0
while your code is using get0
then get1
. 编辑请注意,我用
get1
然后get0
,而你的代码是使用get0
然后get1
。
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