I have a HashMap variable called map were the key is an Integer and the value is a String.
Say for example that there are 100 values in map. I want to search the 100 values for "Donkey" and then I want to return an Integer with the number of "Donkey" in map if there are none then return Integer 0. I tried to use a for loop with map.values() but no luck.
Can someone give me a hint please?
Try this:
int count = Collections.frequency(mapVar.values(), "Donkey");
System.out.println(count);
Let me know whether its worked :)
int value and OP wants an Integer, and variable is called map, not mapVar. ;-)
[1="This donkey is a horse"], [2="My friend is a donkey"]. I know I did not express my question correctly.The Collections.frequency approach is a nice one. However, the assertion that the map.values() didn't work is a bit strange, as it should work. I would add it is especially strange since the Collection passed to the Collections.frequency is the map.values().
// method to do the counting of a particular animal in a map
static Integer countAnimal(String animal, Map<Integer, String> map)
{
int cnt = 0;
for (String val : map.values()) {
if (val.equals(animal)) {
++cnt;
}
}
return new Integer(cnt);
}
public static void main(String[] args)
{
String[] animals = new String[] { "cat", "dog", "pig", "goat", "donkey", "horse", "cow" };
Map<Integer, String> map = new HashMap<>();
// load map for test
Random rnd = new Random();
for (int i = 0; i < 100; ++i) {
String animal = animals[rnd.nextInt(animals.length)];
map.put(new Integer(i), animal);
}
// count how many there are
Map<String, Integer> numAnimals = new HashMap<>();
for (String animal : animals) {
numAnimals.put(animal, countAnimal(animal, map));
}
System.out.println(numAnimals);
// show the cool Collections.frequency approach
Integer count = Collections.frequency(map.values(), "dog");
System.out.println("dog: " + count);
}
Example output:
{horse=18, cat=13, donkey=23, cow=15, goat=17, dog=3, pig=11}
dog: 3
EDIT: an update that allows splitting a string to find the count. Basically countAnimal will split the String retrieved from the map, and then check each token to see if it is an animal. Changed the test case slightly as well. It works based upon the updated comment. It does not consider, however, plurals. The trivial case of "cat" and "cats" is easily handled, but "mouse" and "mice" would be more difficult, and require additional work.
public static void main(String[] args)
{
String[] animals = new String[] { "cat", "dog", "pig", "goat",
"donkey", "horse", "cow" };
Map<Integer, String> map = new HashMap<>();
// load map for test
map.put(1, "My friend has a horse");
map.put(2, "A bear can be big"); // will not be found
map.put(3, "A cat is a loner");
map.put(4, "A dog is man's best friend");
map.put(5, "The cat and the dog are peacefully sleeping");
// count how many there are
Map<String, Integer> numAnimals = new HashMap<>();
for (String animal : animals) {
numAnimals.put(animal, countAnimal(animal, map));
}
System.out.println(numAnimals);
}
static Integer countAnimal(String animal, Map<Integer, String> map)
{
int cnt = 0;
for (String val : map.values()) {
// split the val by space
String[] tokens = val.split("[\\s]+");
for (String token : tokens) {
if (token.equalsIgnoreCase(animal)) {
++cnt;
}
}
}
return new Integer(cnt);
}
Example output:
{horse=1, cat=2, donkey=0, cow=0, goat=0, dog=2, pig=0}
countAnimal method, change val.equals(animal) to val.toUpperCase().contains(animal.toUpperCase()). This approach would handle a sentence approach. However, if you also need "A donkey is a donkey is a donkey" to return 3 (rather than whether a given sentence contains the animal at all), split the String by spaces, and pass to the countAnimal method.map values that you gave as example. However, I am trying to apply this to my program and its not returning anything. My program is using the twitter API and I put tweets gathered in a HashMap called textMap. I don't know if you have experience with the twitter API, but if you do and willing to help me I will put my entire code here for you to see.map.values(). After a bit more investigation, I would suggest taking your next efforts and posting a new question, as it is not possible to debug in the comments.
0for not found, why use a boxedIntegerobject as the result, and not regularintvalue?