I have a hashmap with the values :
1 - 18;
1 - 19;
1 - 20;
3 - 21;
3 - 22;
8 - 23;
8 -24;
8 - 25;
11 - 26;
And I gotta loop it and check whether the key is equal the specific value, which will be a parameter. So, let's say my parameter is the number 3. It should return this to me:
21, 22.
Thanks!
Map<Integer, Integer> map = ...;
for (Integer key : map.keySet()) {
// do something
}
Or
Iterator<Map.Entry<Integer, Integer>> entries = map.entrySet().iterator();
while (entries.hasNext()) {
Map.Entry<Integer, Integer> entry = entries.next();
System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}
EDIT: According to your comment this is what you need, just paste this somewhere and observe and play with it a bit, I tryied to comment the imporant sutff
private void hashMapTest() {
HashMap<Integer, List<Integer>> testMap = new HashMap<>();
int i; // Iterator
// ArrayLists that hold the integer values at specific key
List<Integer> list1 = new ArrayList<>();
List<Integer> list2 = new ArrayList<>();
List<Integer> list3 = new ArrayList<>();
List<Integer> list4 = new ArrayList<>();
// Fill the lists with some demo data.
for (i = 0; i < 5; ++i) {
list1.add(i);
}
for (; i < 10; ++i) {
list2.add(i);
}
for (; i < 15; ++i) {
list3.add(i);
}
for (; i < 20; ++i) {
list4.add(i);
}
// Add the data holders to the map. Note the keys in HashMap must be unique!!
testMap.put(1, list1);
testMap.put(2, list2);
testMap.put(3, list3);
testMap.put(4, list4);
// Let's you want to get the values with the key 3 amd print it out
for (Integer integer : testMap.get(3)) {
Log.d("loop test", "Integer: " + integer);
}
// Now let's say you want to add some value to one of the lists, say key 2
testMap.get(2).add(12314151);
testMap.get(2).add(1231);
testMap.get(2).add(77565);
// And print it
for (Integer integer : testMap.get(2)) {
Log.d("loop test2", "Integer: " + integer);
}
}
Will produce something like this
05-22 21:34:35.765 20092-20092/? D/loop test﹕ Integer: 10
05-22 21:34:35.765 20092-20092/? D/loop test﹕ Integer: 11
05-22 21:34:35.765 20092-20092/? D/loop test﹕ Integer: 12
05-22 21:34:35.766 20092-20092/? D/loop test﹕ Integer: 13
05-22 21:34:35.766 20092-20092/? D/loop test﹕ Integer: 14
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 5
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 6
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 7
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 8
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 9
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 12314151
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 1231
05-22 21:34:35.766 20092-20092/? D/loop test2﹕ Integer: 77565
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