我希望要一个ArrayList<Entry>,类似C++中的pair,
可是Map.Entry是个接口,不能实例化,能够像以下这样写
HashMap<Integer, Integer> G = new HashMap<Integer,Integer>(); G.put(1, 9); G.put(4, 6); G.put(2, 8);G.put(3, 7); ArrayList<Map.Entry<Integer, Integer>> arrayList = new ArrayList<Map.Entry<Integer, Integer>(G.entrySet());
ArrayList<Map.Entry<Integer, Integer>> arrayList = new ArrayList<Map.Entry<Integer, Integer>>(); arrayList.add(new AbstractMap.SimpleEntry(1, 9));
Map<String, Integer> map = new HashMap<String, Integer>(); map.put("d", 2); map.put("c", 1); map.put("b", 1); map.put("a", 3); List<Map.Entry<String, Integer>> infoIds = new ArrayList<Map.Entry<String, Integer>>(map.entrySet()); //排序前 for (int i = 0; i < infoIds.size(); i++) { String id = infoIds.get(i).toString(); System.out.println(id); } //d 2 //c 1 //b 1 //a 3 //排序 Collections.sort(infoIds, new Comparator<Map.Entry<String, Integer>>() { public int compare(Map.Entry<String, Integer> o1, Map.Entry<String, Integer> o2) { //return (o2.getValue() - o1.getValue()); return (o1.getKey()).toString().compareTo(o2.getKey()); } }); //排序后 for (int i = 0; i < infoIds.size(); i++) { String id = infoIds.get(i).toString(); System.out.println(id); } //依据key排序 //a 3 //b 1 //c 1 //d 2 //依据value排序 //a 3 //d 2 //b 1 //c 1
List<Map.Entry<String,Double>> termls = new ArrayList<Map.Entry<String,Double>>(); for(String s: tf.get(i).keySet()) { termls.add(new AbstractMap.SimpleEntry(s, tf.get(i).get(s)*1.0*Math.log10(count*1.0/df.get(s)))); } Collections.sort(termls, new Comparator<Map.Entry<String, Double>>(){ public int compare(Map.Entry<String, Double> o1,Map.Entry<String, Double> o2){ return(o2.getValue().compareTo(o1.getValue())); } } ); System.out.println("line " + (i+1)); for (int ind = 0; ind < termls.size(); ++ind){ System.out.print(termls.get(ind).toString()+" "); } System.out.println();