How do I count the number of times a sequence occurs in a Java string? [closed]

Answer 1

This takes into account the length of "replace"

String text = "a.b.c.d";
String replace = ".";
int count = (text.length()- (text.replaceAll(replace, "").length())) / replace.length();
System.out.println(count)

Answer 2

int index = input.indexOf("is");
int count = 0;
while (index != -1) {
    count++;
    input = input.substring(index + 1);
    index = input.indexOf("is");
}
System.out.println("No of *is* in the input is : " + count);

Answer 3

split on every " " (blank) and check the outcoming string[] with a loop

Answer 4

If you prefer regex, here is a regex solution:

String example = "Hello my is Joeseph. It is very nice to meet you. isWhat a wonderful day it is!";
Matcher m = Pattern.compile("\\bis\\b").matcher(example);

int matches = 0;
while(m.find())
    matches++;

System.out.println(matches);

In this case the "is" in "isWhat" is ignored, because of the \b boundary matcher in the pattern

Answer 5

String haystack = "Hello my is Joeseph. It is very nice to meet you. What a wonderful day it is!";
haystack.toLowerCase();
String needle = "is";

int numNeedles = 0;

int pos = haystack.indexOf(needle);

    while(pos >= 0 ){

      pos = pos + 1;
      numNeedles = numNeedles + 1;

      pos = haystack.indexOf(needle,pos);

    }

 System.out.println("the num of " +needle+ "= " +numNeedles);

Answer 6

You can find the code here. It strangely looks like the Robby's one.