You can simply use the get method. stateIndex.get(nameOfEntry); You set with put and access with get. If you want to get a specific element, just chain the get method for ArrayList. Whatever element = stateIndex.get(nameOfEntry).get(5);// For any type.
So i haven worked that much with HashMaps, but looking at the JavaDoc it should be something like Hashmap<Integer><String> h; int sum = 0; for(int i: h.keySet()) { sum += i; } double percentile = sum/h.size()
Need to be done using Java 8 for(Map.Entry e : map1.entrySet()) { if(e.containsKey(“new”)&& !e.getValue().equals(“”)){ String val1 = (String) e.getValue(); if(e.containsKey(“old”)&& !e.getValue().equals(“”)){ String val2 = (String) e.getValue(); //call the function– This is boolean if(validateMethod(val1, val2)){ // if true Map<String, String> map2 = new HashMap<>(); map2.putAll(e); } } } }
The time efficient way to do this is to create a Bitset with a bit set for all of the integers in all of the sets. Then you can test for membership with a single O(1) call. The problem is that if the combined range of the integers is large, then the Bitset will take … Read more
You should be able to remove the entry with: Map.remove(key)
In a Map the key should always be unique. If you associate a new value to an existing key, it will overwrite the value of the existing entry. You might need to check the interface for Map#put(K, V) method. If the map previously contained a mapping for the key, the old value is replaced by … Read more
You can make a wrapper class for the data structure such as public class DateWrapper{ private int a; private int b; private int c; private Date date; public DateWrapper(int a, int b, int c, Date date){ this.a = a; this.b = b; this.a = c; this.date = date; } // getters and setters } and … Read more
Using Java 8 you can do Map<K, V> map = new HashMap<>(); List<K> list = map.entrySet().stream() .filter(e -> e.getValue() instanceof I) .map(e -> e.getKey()) .collect(Collectors.toList());