Finding repeated words on a string and counting the repetitions

Question

I need to find repeated words on a string, and then count how many times they were repeated. So basically, if the input string is this:

String s = \"House, House         


        

Answer 1

Using java8

private static void findWords(String s, List<String> output, List<Integer> count){
    String[] words = s.split(", ");
    Map<String, Integer> map = new LinkedHashMap<>();
    Arrays.stream(words).forEach(e->map.put(e, map.getOrDefault(e, 0) + 1));
    map.forEach((k,v)->{
        output.add(k);
        count.add(v);
    });
}

Also, use a LinkedHashMap if you want to preserve the order of insertion

private static void findWords(){
    String s = "House, House, House, Dog, Dog, Dog, Dog";
    List<String> output = new ArrayList<>();
    List<Integer> count = new ArrayList<>();
    findWords(s, output, count);
    System.out.println(output);
    System.out.println(count);
}

Output

[House, Dog]
[3, 4]

Answer 2

Once you have got the words from the string it is easy. From Java 10 onwards you can try the following code:

import java.util.Arrays;
import java.util.stream.Collectors;

public class StringFrequencyMap {
    public static void main(String... args) {
        String[] wordArray = {"House", "House", "House", "Dog", "Dog", "Dog", "Dog"};
        var freq = Arrays.stream(wordArray)
                         .collect(Collectors.groupingBy(x -> x, Collectors.counting()));
        System.out.println(freq);
    }
}

Output:

{House=3, Dog=4}

Answer 3

//program to find number of repeating characters in a string
//Developed by Subash<subash_senapati@ymail.com>


import java.util.Scanner;

public class NoOfRepeatedChar

{

   public static void main(String []args)

   {

//input through key board

Scanner sc = new Scanner(System.in);

System.out.println("Enter a string :");

String s1= sc.nextLine();


    //formatting String to char array

    String s2=s1.replace(" ","");
    char [] ch=s2.toCharArray();

    int counter=0;

    //for-loop tocompare first character with the whole character array

    for(int i=0;i<ch.length;i++)
    {
        int count=0;

        for(int j=0;j<ch.length;j++)
        {
             if(ch[i]==ch[j])
                count++; //if character is matching with others
        }
        if(count>1)
        {
            boolean flag=false;

            //for-loop to check whether the character is already refferenced or not 
            for (int k=i-1;k>=0 ;k-- )
            {
                if(ch[i] == ch[k] ) //if the character is already refferenced
                    flag=true;
            }
            if( !flag ) //if(flag==false) 
                counter=counter+1;
        }
    }
    if(counter > 0) //if there is/are any repeating characters
            System.out.println("Number of repeating charcters in the given string is/are " +counter);
    else
            System.out.println("Sorry there is/are no repeating charcters in the given string");
    }
}

Answer 4

I hope this will help you

public void countInPara(String str) {

    Map<Integer,String> strMap = new HashMap<Integer,String>();
    List<String> paraWords = Arrays.asList(str.split(" "));
    Set<String> strSet = new LinkedHashSet<>(paraWords);
    int count;

    for(String word : strSet) {
        count = Collections.frequency(paraWords, word);
        strMap.put(count, strMap.get(count)==null ? word : strMap.get(count).concat(","+word));
    }

    for(Map.Entry<Integer,String> entry : strMap.entrySet())
        System.out.println(entry.getKey() +" :: "+ entry.getValue());
}

Answer 5

import java.util.HashMap;
import java.util.Scanner;
public class class1 {
public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    String inpStr = in.nextLine();
    int key;

    HashMap<String,Integer> hm = new HashMap<String,Integer>();
    String[] strArr = inpStr.split(" ");

    for(int i=0;i<strArr.length;i++){
        if(hm.containsKey(strArr[i])){
            key = hm.get(strArr[i]);
            hm.put(strArr[i],key+1);

        }
        else{
            hm.put(strArr[i],1);
        }   
    }
    System.out.println(hm);
}

}