How to count frequency of characters in a string?

by

You can use a java Map and map a char to an int. You can then iterate over the characters in the string and check if they have been added to the map, if they have, you can then increment its value.

For example:

HashMap<Character, Integer> map = new HashMap<Character, Integer>();
String s = "aasjjikkk";
for (int i = 0; i < s.length(); i++) {
    char c = s.charAt(i);
    Integer val = map.get(c);
    if (val != null) {
        map.put(c, new Integer(val + 1));
    }
    else {
       map.put(c, 1);
   }
}

At the end you will have a count of all the characters you encountered and you can extract their frequencies from that.

Alternatively, you can use Bozho’s solution of using a Multiset and counting the total occurences.

More Related Contents:

  1. incompatible types required char found java.lang.string
  2. All possible Angram String combinations in java [closed]
  3. Regex for converting xml tags key to camel case
  4. Change date format in a Java string
  5. How to split a string with any whitespace chars as delimiters
  6. What is meant by immutable?
  7. What is the purpose of the expression “new String(…)” in Java?
  8. How does the String class override the + operator?
  9. How to format strings in Java
  10. How to convert Java String into byte[]?
  11. How to find nth occurrence of character in a string?
  12. Using Java to find substring of a bigger string using Regular Expression
  13. How can I use “.” as the delimiter with String.split() in java [duplicate]
  14. Converting Secret Key into a String and Vice Versa
  15. Java: Getting a substring from a string starting after a particular character
  16. Reverse a given sentence in Java
  17. Extract string between two strings in java
  18. formatting a string to a currency format in jasper report
  19. How to check if a string starts with one of several prefixes?
  20. How to convert a String into an ArrayList?
  21. Remove end of line characters from Java string
  22. java.lang.NumberFormatException: empty String
  23. String Deduplication feature of Java 8
  24. Convert String to Uri
  25. Calculating frequency of each word in a sentence in java
  26. intern() behaving differently in Java 6 and Java 7
  27. Remove all non-“word characters” from a String in Java, leaving accented characters?
  28. Fastest way to strip all non-printable characters from a Java String
  29. Simple way to sort strings in the (case sensitive) alphabetical order
  30. Java printf using variable field size?

Leave a Comment