Want to learn how to count character occurrences in Java String?
Below is the program that uses a Map to store chars as keys and the number of occurrences as values.
class Test { public static void main(String[] args) { String str = "moiujjmhrqdoasdsooqavvae"; Map<Character, Integer> map = new HashMap<>(); for (int i = 0; i < str.length(); i++) { // if the map already contains char, then increase the value by 1 if (map.containsKey(str.charAt(i))) { map.put(str.charAt(i), map.get(str.charAt(i)) + 1); } else { // else put the char into a map for the first time and add value of 1 as the number of occurrences map.put(str.charAt(i), 1); } } System.out.println(map); } }
Output: {a=3, d=2, e=1, h=1, i=1, j=2, m=2, o=4, q=2, r=1, s=2, u=1, v=2}
How to count occurences of a specific char in a Java String?
Below is the program that counts occurrences of a specific char in a String.
class Test { public static void main(String[] args) { int count = 0; String str = "moiujjmhrqdoasdsooqavvae"; // count occurrences of a char 'o' for (int i = 0; i < str.length(); i++) { if (str.charAt(i) == 'o') { count++; } } System.out.println("Character 'o' occurred: " + count + " times."); } }
Output: Character ‘o’ occurred: 4 times.