count characters code example

Example 1: count letters numbers and characters

public static String countLetter(String str){
    String abc=str;
    int a=0,b=0;
    while(str.length()>0){
        int i=0;
        String ch=str.substring(i,i+1);
        if(ch.matches(".*[a-zA-Z].*")){
            a++;
        }else if (ch.matches(".*[0-9].*")){
            b++;
        }
        str=str.substring(i+1);
    }
    return abc + " has "+a+" letters "+b+" digit 
          and "+(abc.length()-(a+b))+" other characters ";
      
      
OR+++++++++++++++++++++++++++++++++
      
      
  static void findSum(String str)
{
   int total= str.length();
   str = str.replaceAll("\\s", "");
   int num =0;
   int letter=0;
   int i=0;
   while(i<str.length()){
      char ch = str.charAt(i);
      // if current character is a digit
      if (Character.isDigit(ch))
         num ++;
         // if current character is an alphabet
      else {
         letter++;
      }
      i++;
   }
   System.out.println(letter + " letters -> "+num +
                      " numbers -> "+ (total-letter-num) + " other chars");
}

Example 2: how to count words in string

String str = "I am happy and why not
  and why are you not happy and you should be";
        String [] arr = str.split(" ");
        Map<String, Integer> map = new HashMap<>();

        for (int i=0 ; i < arr.length ; i++){
                if (!map.containsKey(arr[i])){
                    map.put(arr[i],1);
                } else{
                    map.put(arr[i],map.get(arr[i])+1);
                }
        }
        for(Map.Entry<String, Integer> each : map.entrySet()){

  System.out.println(each.getKey()+" occures " + each.getValue() + " times");
        }

Example 3: counting special characters

int count = str.length() - str.replaceAll("\\$","").length();

Example 4: charcount

//Calculate the times a character occurs
	public static int charCount(String userInput) {
		
		//convert the string to a char array
		char[] StringArray = userInput.toCharArray();
		
		//hashmap that stores the characters. key will be the time it occures
		HashMap<Character, Integer>charCount = new HashMap<Character, Integer>();