A program that counts the letters in string in Java - java

I have to create a program that counts the letters in string and I have a little problem with that.
This is my code in main:
Scanner sc = new Scanner(System.in);
String str;
int count;
System.out.println("Enter some text: ");
str = sc.nextLine();
char ch;
System.out.println("Letters: ");
for (ch = (char) 65; ch <= 90; ch++) {
count = 0;
for (int i = 0; i < str.length(); i++) {
if (ch == str.charAt(i) || (ch + 32) == str.charAt(i)) {
count++;
}
}
if (count > 0) {
System.out.println(ch + ": " + count);
}
}
Everything looks fine, but the output should not be in alphabetical order, rather ordered by the number of letters descending.
For example, if you input Hello World, the output should be something like this:
L: 3
O: 2
H: 1
D: 1
E: 1
R: 1
W: 1
The output would be sorted in descending order of letter frequency. That means the most frequent letter should appear first and the least last.
The order for letters that appears in equal proportions must be in alphabetical order.

The problem is that your outer loop browse the letters in alphabetical order, and that's where you display the count.
I would instead recommend browsing the input string with a single loop, updating the count of each letter in a Map<Character, Integer> as I encounter them.
Then once the input String has been consumed, I would sort the Map by descending values, and print each key/value pair.
Map<Character, Integer> lettersCount = new HashMap<>();
for (int i=0; i <str.length(); i++) {
Character current = str.charAt(i);
if (Character.isLetter(current)) {
Integer previousCount = lettersCount.get(current);
if (previousCount != null) {
lettersCount.put(current, previousCount + 1);
} else {
lettersCount.put(current, 1);
}
}
}
List<Map.Entry<Character, Integer>> list = new LinkedList<Map.Entry<Character, Integer>>( lettersCount.entrySet() );
Collections.sort( list, new Comparator<Map.Entry<Character, Integer>>()
{
public int compare( Map.Entry<Character, Integer> o1, Map.Entry<Character, Integer> o2 )
{
return (o2.getValue()).compareTo( o1.getValue() );
}
} );
for (Map.Entry<Character, Integer> entry : list) {
System.out.println(entry.getKey() + " : " + entry.getValue());
}
You can try it out on ideone.
As you can see, sorting a Map by values isn't trivial :-/

If you want to sort the results then you'll have to store the results & then iterate over them by their count descending to print in order
The best data structure to store them into would be a heap, keyed off of count. Java supplies such a data structure as java.util.PriorityQueue which can take a comparator function which first compares count & then character
https://docs.oracle.com/javase/7/docs/api/java/util/PriorityQueue.html

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
String str;
int count;
System.out.println("Enter some text: ");
str = sc.nextLine();
char ch;
System.out.println("Letters: ");
LinkedHashMap<String, Integer> charCountMap = new LinkedHashMap<String, Integer>();
for (ch = (char) 65; ch <= 90; ch++) {
count = 0;
for (int i = 0; i < str.length(); i++) {
if (ch == str.charAt(i) || (ch + 32) == str.charAt(i)) {
count++;
}
}
if (count > 0) {
System.out.println(ch + ": " + count);
charCountMap.put(ch + "", count);
}
}
LinkedHashMap<String, Integer> sortedMapBasedOnValues = sortHashMapByValues(charCountMap);
for (Map.Entry<String, Integer> entry : sortedMapBasedOnValues.entrySet()) {
System.out.println("Key : " + entry.getKey() + " Value : " + entry.getValue());
}
}
// Following method used from
// http://stackoverflow.com/questions/8119366/sorting-hashmap-by-values
public static LinkedHashMap<String, Integer> sortHashMapByValues(LinkedHashMap<String, Integer> passedMap) {
List<String> mapKeys = new ArrayList<>(passedMap.keySet());
List<Integer> mapValues = new ArrayList<>(passedMap.values());
Collections.sort(mapValues, Collections.reverseOrder());
Collections.sort(mapKeys);
LinkedHashMap<String, Integer> sortedMap = new LinkedHashMap<>();
Iterator<Integer> valueIt = mapValues.iterator();
while (valueIt.hasNext()) {
Integer val = valueIt.next();
Iterator<String> keyIt = mapKeys.iterator();
while (keyIt.hasNext()) {
String key = keyIt.next();
Integer comp1 = passedMap.get(key);
Integer comp2 = val;
if (comp1.equals(comp2)) {
keyIt.remove();
sortedMap.put(key, val);
break;
}
}
}
return sortedMap;
}
}

Related

Count occurrences & print highest occurred char 'n' times

I was trying to solve some programs, I came across this interesting one, where we need to print the highest occurred character n times & likewise for other characters.
Ex: Input string : "please stay hydrated"
Output string : "aaaeeettyysplhdr"
I was only able to solve half way, where we print the highest occurred character & the times it has occurred using a HashMap.
public static void repeatedChar(String str) {
char[] chars = str.toCharArray();
Map<Character, Integer> map = new HashMap<>();
for (Character c : chars) {
if (map.containsKey(c)) {
map.put(c, map.get(c) + 1);
} else {
map.put(c, 1);
}
}
//Now To find the highest character repeated
int max = 0;
//setting to a by default
char maxCharacter = 'a';
for (Map.Entry<Character, Integer> entry : map.entrySet()) {
System.out.println("Key = " + entry.getKey() + ": Value " + entry.getValue());
if (max < entry.getValue()) {
max = entry.getValue();
maxCharacter = entry.getKey();
}
}
System.out.println("Max Character = " + maxCharacter + " Max Count : " + max);
}
This currently prints the highest occured character & the number of times that character has occurred. Can someone please let me know how to proceed further? Thanks
In order to get the desired output you need to sort your map by value. But since a hashmap is not meant to be sorted, but accessed fast, you could add all entries to a list and sort the list. Something like:
import java.util.Map.Entry;
import java.util.Comparator;
....
public static void repeatedChar(String str) {
char[] chars = str.toCharArray();
Map<Character, Integer> map = new HashMap<>();
for (Character c : chars) {
if (map.containsKey(c)) {
map.put(c, map.get(c) + 1);
} else {
map.put(c, 1);
}
}
//add map entries to list
List<Entry<Character, Integer>> list = new ArrayList<>(map.entrySet());
//sort entries by value descending
list.sort(Entry.comparingByValue(Comparator.reverseOrder()));
//print
for (Entry<Character, Integer> entry : list) {
for (int i = 0; i < entry.getValue(); i++){
System.out.print(entry.getKey());
}
}
}
and if you fancy a stream approach:
import java.util.Comparator;
import java.util.Map;
import java.util.function.Function;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
....
public static void repeatedCharWithStreams(String str) {
String output =
Pattern.compile("")
.splitAsStream(str)
.collect(Collectors.groupingBy(Function.identity(),Collectors.counting()))
.entrySet().stream()
.sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
.map(e -> e.getKey().repeat(e.getValue().intValue()))
.collect(Collectors.joining());
System.out.println(output);
}

Least repeating chararcter in a string

I'm trying to find the least repeating character in a string ,it works for some input but it fails for some input.
Map<Character, Integer> map = new HashMap<Character, Integer> ();
String s = "abcdabcdabcdacd";
char[] chars = s.toCharArray();
for (Character ch: chars) {
if (map.containsKey(ch)) {
map.put(ch, map.get(ch) + 1);
} else {
map.put(ch, 1);
}
}
Set<Character> keys = map.keySet();
for (Character ch: keys) {
if (map.get(ch) ==1) {
System.out.println(ch + " ");
}
}
I expect the output to be b but it doesn't show anything.
If i give aabaa as the input then it shows b and that's correct.
As I commented already, you only check for characters which only occur once, not for the least occurrence.
You can change your code by this:
public class PrintB {
public static void main(String[] args) {
Map<Character, Integer> map = new HashMap<>();
String s = "abcdabcdabcdacd";
char[] chars = s.toCharArray();
for (Character ch: chars) {
if (map.containsKey(ch)) {
map.put(ch, map.get(ch) + 1);
} else {
map.put(ch, 1);
}
}
Set<Character> keys = map.keySet();
boolean broken = false;
for ( int i = 0; i < s.length(); i++ ) { // the max will be s.length()
for (Character ch : keys) {
if (map.get(ch) == i) { // this amount is checked for each char
System.out.println(ch + " ");
broken = true;
}
}
if ( broken ) {
i = s.length(); // sure, there are other ways to break out of the loop
}
}
}
}
Using streams you may simply do:
final String s = "abcdabcdabcdacd";
String leastRepeated =
s.chars().mapToObj(i -> Character.toString((char) i)) // map to Stream<String>
.collect(Collectors.toMap(k -> k, v -> 1, Integer::sum)) // Map<String, Integer>
.entrySet().stream() // stream over map
.min(Comparator.comparing(Entry::getValue)) // comparing values in map
.get().getKey(); // get resp entry
which outputs:
b
You have to read the whole map to get the min occurrence, so you can't print in the loop, you should instead collect chars with min occurence, and then print them.
public static void main(String[] args) {
Map<Character, Integer> map = new HashMap<>();
String s = "abcdaybcdabcdacdz";
char[] chars = s.toCharArray();
for (Character ch: chars) {
if (map.containsKey(ch)) {
map.put(ch, map.get(ch) + 1);
} else {
map.put(ch, 1);
}
}
List<Character> reps = new ArrayList<>();
Integer count = chars.length;
Set<Entry<Character, Integer>> entries = map.entrySet();
for (Entry<Character, Integer> entry : entries) {
Integer n = entry.getValue();
Character c = entry.getKey();
if(n==count) {
reps.add(c);
}else if (n<count) {
reps = new ArrayList<>();
reps.add(c);
count = n;
}
}
for (Character character : reps) {
System.out.println(character);
}
}
The reason your code doesn't work the way you would want it to is because your last code block is only printing if the character is being repeated once and only once:
for (Character ch: keys) {
if (map.get(ch) ==1) {
System.out.println(ch + " ");
}
However by using the Collections.min method we can find the lowest map value which we can then use to find the character it belongs to from map keys. Here is the complete code with context:
/**
* #return an array of Character objects that have occured the
* least amount of times in the given {#code String} parameter.
* <i>Note that all whitespaces found within the {#code String} will be ignored </i>
*/
public static Character[] getLeastRepeatingCharacters(String text) {
Map<Character, Integer> map = new HashMap<Character, Integer> ();
/*
* Remove all whitespaces from the text as we don't
* want to include them in our comparison oprations
*/
text = text.replaceAll("\\s+","");
for (Character ch : text.toCharArray()) {
if (map.containsKey(ch)) {
map.put(ch, map.get(ch) + 1);
}
else if (ch != '\0') {
map.put(ch, 1);
}
}
/*
* Get map value that occurs the least amount of times
*/
int leastOccuranceValue = Collections.min(map.values());
java.util.List<Character> leastOccurances = new java.util.ArrayList<>();
/*
* Iterate through the map, find all characters that have
* occured the least amount of times and add them to a list
*/
for (java.util.Map.Entry<Character, Integer> entry : map.entrySet()) {
if (entry.getValue().equals(leastOccuranceValue)) {
leastOccurances.add(entry.getKey());
}
}
return leastOccurances.toArray(new Character[0]);
}
public static void main(String[] args) {
String text = "abcdabcdabcdacd";
Character[] leastRepeating = getLeastRepeatingCharacters(text);
String log = "Array of charactes that repeated the least amount of times in text '%s':%n%s";
System.out.printf(log, text, Arrays.toString(leastRepeating));
}
Output:
Your string sample:
Array of charactes that repeated the least amount of times in text 'abcdabcdabcdacd ':
[b]
String sample provided by Stultuske:
Array of charactes that repeated the least amount of times in text 'kambcxdabcdalbcdacd ':
[x, k, l, m]

Get Hashmap Top 3 Keys

I have a hashmap storing the number of occurrences of character in a text. I am trying to print out the top 3 occurrences, but it is printing incorrectly.
int max = 1000000000;
for (int i = 1; i <= 3; i++) {
for (Character key : list.keySet()) {
if (list.get(key) < max) {
max = list.get(key);
System.out.println(i + ": " + key + " " + list.get(key));
break;
}
}
}
With Java 8 you can use the code below(*):
List<Entry<Character, Integer>> top3 = map.entrySet().stream()
.sorted(comparing(Entry::getValue, reverseOrder()))
.limit(3)
.collect(toList());
(*) with the following imports:
import static java.util.Comparator.comparing;
import static java.util.Comparator.reverseOrder;
import static java.util.stream.Collectors.toList;
You could modify your program to this form:
for (int i = 1; i <= 3; i++) {
int max = -1;
Character maxKey = 'a';
for (Character key : list.keySet()) {
if (list.get(key) > max) {
max = list.get(key);
maxKey = key;
}
}
System.out.println(i + ": " + maxKey + " " + max );
list.remove(maxKey);
}
You need to sort your entries by number of occurences and get the top 3:
List<Entry<Character, Integer>> entryList = new ArrayList<>(list.entrySet());
Collections.sort(entryList, new Comparator<Entry<Character, Integer>>(){
#Override
public int compare(Entry<Character, Integer> e1, Entry<Character, Integer> e2) {
return e2.getValue() - e1.getValue(); // descending order
}
});
// now let's get the top 3
List<Character> top3 = new ArrayList<>(3);
for(Entry<Character, Integer> e : entryList) {
top3.add(e.getValue());
if(top3.size() == 3) {
break;
}
}
Here's a solution using Java 8 streams, based on the one provided by #assylias. It performs the complete task of collecting character counts from a String into a Map and selecting the top 3 entries.
import java.util.ArrayList;
import static java.util.Comparator.*;
import java.util.List;
import java.util.Map.Entry;
import static java.util.stream.Collectors.*;
public class Stream {
public static void main(final String[] args) {
final String text = "hello stackoverflow, let's count these character occurrences!";
final char[] charArray = text.toCharArray();
final List<Character> characters = new ArrayList<Character>(text.length());
for (final char c : charArray) {
characters.add(c);
}
final List<Entry<Character, Long>> top3 = characters.stream()
.collect(groupingBy(Character::charValue, counting()))
.entrySet().stream()
.sorted(comparing(Entry::getValue, reverseOrder())).limit(3).collect(toList());
System.out.println(top3);
}
}
Output:
[e=8, c=7, =6]

How to find the most frequently occurring character in a string with Java?

Given a paragraph as input, find the most frequently occurring character. Note that the case of the character does not matter. If more than one character has the same maximum occurring frequency, return all of them
I was trying this question but I ended up with nothing. Following is the code that I tried but it has many errors I am unable to correct:
public class MaximumOccuringChar {
static String testcase1 = "Hello! Are you all fine? What are u doing today? Hey Guyz,Listen! I have a plan for today.";
public static void main(String[] args)
{
MaximumOccuringChar test = new MaximumOccuringChar();
char[] result = test.maximumOccuringChar(testcase1);
System.out.println(result);
}
public char[] maximumOccuringChar(String str)
{
int temp = 0;
int count = 0;
int current = 0;
char[] maxchar = new char[str.length()];
for (int i = 0; i < str.length(); i++)
{
char ch = str.charAt(i);
for (int j = i + 1; j < str.length(); j++)
{
char ch1 = str.charAt(j);
if (ch != ch1)
{
count++;
}
}
if (count > temp)
{
temp = count;
maxchar[current] = ch;
current++;
}
}
return maxchar;
}
}
You already got your answer here: https://stackoverflow.com/a/21749133/1661864
It's a most easy way I can imagine.
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class MaximumOccurringChar {
static final String TEST_CASE_1 = "Hello! Are you all fine? What are u doing today? Hey Guyz,Listen! I have a plan for today. Help!";
public static void main(String[] args) {
MaximumOccurringChar test = new MaximumOccurringChar();
List<Character> result = test.maximumOccurringChars(TEST_CASE_1, true);
System.out.println(result);
}
public List<Character> maximumOccurringChars(String str) {
return maximumOccurringChars(str, false);
}
// set skipSpaces true if you want to skip spaces
public List<Character> maximumOccurringChars(String str, Boolean skipSpaces) {
Map<Character, Integer> map = new HashMap<>();
List<Character> occurrences = new ArrayList<>();
int maxOccurring = 0;
// creates map of all characters
for (int i = 0; i < str.length(); i++) {
char ch = str.charAt(i);
if (skipSpaces && ch == ' ') // skips spaces if needed
continue;
if (map.containsKey(ch)) {
map.put(ch, map.get(ch) + 1);
} else {
map.put(ch, 1);
}
if (map.get(ch) > maxOccurring) {
maxOccurring = map.get(ch); // saves max occurring
}
}
// finds all characters with maxOccurring and adds it to occurrences List
for (Map.Entry<Character, Integer> entry : map.entrySet()) {
if (entry.getValue() == maxOccurring) {
occurrences.add(entry.getKey());
}
}
return occurrences;
}
}
Why don't you simply use N letter buckets (N=number of letters in alphabet) ? Just go along the string and increment the corresponding letter bucket. Time complexity O(n), space complexity O(N)
This method allows you to find the most frequently occurring character in a string:
public char maximumOccuringChar(String str) {
return str.chars()
.mapToObj(x -> (char) x) // box to Character
.collect(groupingBy(x -> x, counting())) // collect to Map<Character, Long>
.entrySet().stream()
.max(comparingByValue()) // find entry with largest count
.get() // or throw if source string is empty
.getKey();
}
import java.util.Scanner;
public class MaximumOccurringChar{
static String testcase1 = "Hello! Are you all fine? What are u doing today? Hey Guyz,Listen! I have a plan for today.";
public static void main(String[] args) {
MaximumOccurringChar test = new MaximumOccurringChar();
String result = test.maximumOccuringChar(testcase1);
System.out.println(result);
}
public String maximumOccuringChar(String str) {
int temp = 0;
int count = 0;
int current = 0;
int ind = 0;
char[] arrayChar = {'a','b' , 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'};
int[] numChar = new int[26];
char ch;
String s="";
str = str.toLowerCase();
for (int i = 0; i < 26; i++) {
count = 0;
for (int j = 0; j < str.length(); j++) {
ch = str.charAt(j);
if (arrayChar[i] == ch) {
count++;
}
}
numChar[i] = count++;
}
temp = numChar[0];
for (int i = 1; i < numChar.length; i++) {
if (temp < numChar[i]) {
temp = numChar[i];
ind = i;
break;
}
}
System.out.println(numChar.toString());
for(int c=0;c<26;c++)
{
if(numChar[c]==temp)
s+=arrayChar[c]+" ";
}
return s;
}
}
Algorithm:-
Copying the String character by character to LinkedHashMap.
If its a new character then insert new character , 1.
If character is already present in the LinkedHashMap then update the value by incrementing by 1.
Iterating over the entry one by one and storing it in a Entry object.
If value of key stored in entry object is greater than or equal to current entry then do nothing
Else, store new entry in the Entry object
After looping through, simply print the key and value from Entry object.
public class Characterop {
public void maxOccur(String ip)
{
LinkedHashMap<Character, Integer> hash = new LinkedHashMap();
for(int i = 0; i<ip.length();i++)
{
char ch = ip.charAt(i);
if(hash.containsKey(ch))
{
hash.put(ch, (hash.get(ch)+1));
}
else
{
hash.put(ch, 1);
}
}
//Set set = hash.entrySet();
Entry<Character, Integer> maxEntry = null;
for(Entry<Character,Integer> entry : hash.entrySet())
{
if(maxEntry == null)
{
maxEntry = entry;
}
else if(maxEntry.getValue() < entry.getValue())
{
maxEntry = entry;
}
}
System.out.println(maxEntry.getKey());
}
public static void main(String[] args) {
Characterop op = new Characterop();
op.maxOccur("AABBBCCCCDDDDDDDDDD");
}
}
The Big O below solution is just o(n). Please share your opinion on it.
public class MaxOccuringCahrsInStr {
/**
* #param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String str = "This is Sarthak Gupta";
printMaxOccuringChars(str);
}
static void printMaxOccuringChars(String str) {
char[] arr = str.toCharArray();
/* Assuming all characters are ascii */
int[] arr1 = new int[256];
int maxoccuring = 0;
for (int i = 0; i < arr.length; i++) {
if (arr[i] != ' ') { // ignoring space
int val = (int) arr[i];
arr1[val]++;
if (arr1[val] > maxoccuring) {
maxoccuring = arr1[val];
}
}
}
for (int k = 0; k < arr1.length; k++) {
if (maxoccuring == arr1[k]) {
char c = (char) k;
System.out.print(c + " ");
}
}
}
}
function countString(ss)
{
var maxChar='';
var maxCount=0;
for(var i=0;i<ss.length;i++)
{
var charCount=0;
var localChar=''
for(var j=i+1;j<ss.length;j++)
{
if(ss[i]!=' ' && ss[i] !=maxChar)
if(ss[i]==ss[j])
{
localChar=ss[i];
++charCount;
}
}
if(charCount>maxCount)
{
maxCount=charCount;
maxChar=localChar;
}
}
alert(maxCount+""+maxChar)
}
Another way to solve it. A simpler one.
public static void main(String[] args) {
String str= "aaaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbcddddeeeeee";
String str1 = "dbc";
if(highestOccuredChar(str) != ' ')
System.out.println("Most Frequently occured Character ==> " +Character.toString(highestOccuredChar(str)));
else
System.out.println("The String doesn't have any character whose occurance is more than 1");
}
private static char highestOccuredChar(String str) {
int [] count = new int [256];
for ( int i=0 ;i<str.length() ; i++){
count[str.charAt(i)]++;
}
int max = -1 ;
char result = ' ' ;
for(int j =0 ;j<str.length() ; j++){
if(max < count[str.charAt(j)] && count[str.charAt(j)] > 1) {
max = count[str.charAt(j)];
result = str.charAt(j);
}
}
return result;
}
public void countOccurrence(String str){
int length = str.length();
char[] arr = str.toCharArray();
HashMap<Character, Integer> map = new HashMap<>();
int max = 0;
for (char ch : arr) {
if(ch == ' '){
continue;
}
if (map.containsKey(ch)) {
map.put(ch, map.get(ch) + 1);
} else {
map.put(ch, 1);
}
}
Set<Character> set = map.keySet();
for (char c : set) {
if (max == 0 || map.get(c) > max) {
max = map.get(c);
}
}
for (Character o : map.keySet()) {
if (map.get(o).equals(max)) {
System.out.println(o);
}
}
System.out.println("");
}
public static void main(String[] args) {
HighestOccurence ho = new HighestOccurence();
ho.countOccurrence("aabbbcde");
}
public void stringMostFrequentCharacter() {
String str = "My string lekdcd dljklskjffslk akdjfjdkjs skdjlaldkjfl;ak adkj;kfjflakj alkj;ljsfo^wiorufoi$*#&$ *******";
char[] chars = str.toCharArray(); //optionally - str.toLowerCase().toCharArray();
int unicodeMaxValue = 65535; // 4 bytes
int[] charCodes = new int[unicodeMaxValue];
for (char c: chars) {
charCodes[(int)c]++;
}
int maxValue = 0;
int maxIndex = 0;
for (int i = 0; i < unicodeMaxValue; i++) {
if (charCodes[i] > maxValue) {
maxValue = charCodes[i];
maxIndex = i;
}
}
char maxChar = (char)maxIndex;
System.out.println("The most frequent character is >" + maxChar + "< - # of times: " + maxValue);
}
For Simple String Manipulation, this program can be done as:
package abc;
import java.io.*;
public class highocc
{
public static void main(String args[])throws IOException
{
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter any word : ");
String str=in.readLine();
str=str.toLowerCase();
int g=0,count,max=0;;
int ar[]=new int[26];
char ch[]={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
for(int i=0;i<ch.length;i++)
{
count=0;
for(int j=0;j<str.length();j++)
{
char ch1=str.charAt(j);
if(ch[i]==ch1)
count++;
}
ar[i]=(int) count;
}
max=ar[0];
for(int j=1;j<26;j++)
{
if(max<ar[j])
{
max=ar[j];
g=j;
}
}
System.out.println("Maximum Occurence is "+max+" of character "+ch[g]);
}
}
Sample Input1: Pratik is a good Programmer
Sample Output1: Maximum Occurence is 3 of character a
Sample Input2: hello WORLD
Sample Output2: Maximum Occurence is 3 of character l
maxOccu m = new maxOccu();
String str = "moinnnnaaooooo";
char[] chars = str.toCharArray();
Arrays.sort(chars);
str = new String(chars);
System.out.println(str);
m.maxOccurence(str);
void maxOccurence(String str) {
char max_char = str.charAt(0),
cur_char,
prev = str.charAt(0);
int cur_count = 0,
max_count = 0,
n;
n = str.length();
for (int i = 0; i < n; i++) {
cur_char = str.charAt(i);
if (cur_char != prev) cur_count = 0;
if (str.charAt(i) == cur_char) {
cur_count++;
}
if (cur_count > max_count) {
max_count = cur_count;
max_char = cur_char;
}
prev = cur_char;
}
System.out.println(max_count + "" + max_char);
}
public class HigestOccurredCharTest {
public static void main(String[] args) {
System.out.println("Enter the char string to check higest occurrence");
Scanner scan = new Scanner(System.in);
String str = scan.next();
if(str != null && !str.isEmpty()){
Map<Character, Integer> map = countOccurrence(str);
getHigestOccurrenceChar(map);
}else{
System.out.println("enter valid string");
}
}
public static Map<Character, Integer> countOccurrence(String str){
char strArr[] = str.toCharArray();
Map<Character, Integer> map = new HashMap<Character , Integer>();
for (Character ch : strArr) {
if(map.containsKey(ch)){
map.put(ch, map.get(ch)+1);
}else{
map.put(ch, 1);
}
}
return map;
}
public static void getHigestOccurrenceChar(Map<Character, Integer> map){
Character ch = null;
Integer no = 0;
Set<Entry<Character, Integer>> entrySet = map.entrySet();
for (Entry<Character, Integer> entry : entrySet) {
if(no != 0 && ch != null){
if(entry.getValue() > no){
no = entry.getValue();
ch = entry.getKey();
}
}else{
no = entry.getValue();
ch = entry.getKey();
}
}
System.out.println(ch+ " Higest occurrence char is "+ no);
}
}
Try Like that:-
string inputString = "COMMECEMENT";
List<Tuple<char, int>> allCharListWithLength = new List<Tuple<char, int>>();
List<char> distinchtCharList = inputString.Select(r => r).Distinct().ToList();
for (int i = 0; i < distinchtCharList.Count; i++)
{
allCharListWithLength.Add(new Tuple<char, int>(distinchtCharList[i], inputString.Where(r => r ==
distinchtCharList[i]).Count()));
}
Tuple<char, int> charWithMaxLength = allCharListWithLength.Where(r => r.Item2 == allCharListWithLength.Max(x => x.Item2)).FirstOrDefault();
Question: Frequently occurring Character in a String
Method 1: Using HashMap
public class t1{
public static void main(String a[]){
Map<Character, Integer> map = new HashMap<>();
String a1 = "GiinnniiiiGiiinnnnnaaaProtijayi";
for(char ch : a1.toCharArray()) {map.put(ch, map.getOrDefault(ch,0)+1);}//for
System.out.println(map);
char maxchar = 0 ;
int maxvalue = Collections.max(map.values());
System.out.println("maxvalue => " + maxvalue);
for( Entry<Character,Integer> entry : map.entrySet()) {
if(entry.getValue() == maxvalue) {
System.out.println("most frequent Character => " + entry.getKey());
}
}//for
}
}
Method 2 : Using count of alphabets in Python
str = "GiinnniiiiGiiinnnnnaaaProtijayi";
count = [0]*256
maxcount= -1
longestcharacter =""
# Traversing through the string and maintaining the count of
# each character
for ch in str:count[ord(ch)] += 1;
for ch in str:
if( maxcount < count[ord(ch)] ):
maxcount = count[ord(ch)]
longestcharacter = ch
print(longestcharacter)
print(maxcount)
IN Java :
public class t1{
public static void main(String[] args) {
String a = "GiinnniiiiGiiinnnnnaaaProtijayi";
int[] count = new int[256];
for (int i = 0; i < a.length(); i++) {
char ch = a.charAt(i);
count[ch] +=1;
}//for
int maxcount = -1 ;
char longest = 0 ;
for( char ch : a.toCharArray()) {
if(count[ch] > maxcount) {
maxcount = count[ch];
longest = ch ;
}//if
}//for
System.out.println(longest);
System.out.println(maxcount);
}//main
}
Method 3: Using collections.Counter().most_common()
import collections
a = "GiinnniiiiGiiinnnnnaaaProtijayi";
fullDictionary = collections.Counter(a).most_common()
FirstElementWithCount = fullDictionary[0]
print(FirstElementWithCount)
FirstElementWithoutCount = FirstElementWithCount[0]
print(FirstElementWithoutCount)
Method 4: Using sorted and key = lambda ch : ch[1]
a = "GiinnniiiiGiiinnnnnaaaProtijayi";
d = {}
for ch in a: d[ch] = d.get(ch, 0) + 1
fullDictionary = sorted(d.items(), key=lambda ch :ch[1], reverse=True)
print(fullDictionary)
FirstElement = fullDictionary[0][0]
print(FirstElement)
package com.practice.ArunS;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.TreeMap;
public class HighestFrequencyElement {
/*
* CONTENTSERV=N(2),T(2),E(2) SearchSort=S(2),r(2)
* HighestFrequencyElement=E(5)
*/
public static void main(String[] args) {
String str = "CONTENTSERV";
findHighestFrequencyElement(str);
}
private static void findHighestFrequencyElement(String str) {
System.out.println("Original String:" + str);
Map<String, Integer> myMap = new TreeMap<String, Integer>();
char[] ch = str.toCharArray();
for (int i = 0; i < str.length(); i++) {
if (myMap.containsKey(Character.toString(ch[i]))) {
Integer value = myMap.get(Character.toString(ch[i]));
myMap.replace(Character.toString(ch[i]), ++value);
} else {
myMap.put(Character.toString(ch[i]), 1);
}
} // end of foor loop
Comparator<Entry<String, Integer>> valueComparator = new Comparator<Entry<String, Integer>>() {
#Override
public int compare(Entry<String, Integer> e1, Entry<String, Integer> e2) {
Integer v1 = e1.getValue();
Integer v2 = e2.getValue();
return v2-v1;
}
};
// Sort method needs a List, so let's first convert Set to List in Java
List<Entry<String, Integer>> listOfEntries = new ArrayList<Entry<String, Integer>>(myMap.entrySet());
// sorting HashMap by values using comparator
Collections.sort(listOfEntries, valueComparator);
for(int i=0;i<listOfEntries.size();i++){
if(listOfEntries.get(0).getValue()==listOfEntries.get(i).getValue()){
System.out.println(listOfEntries.get(i));
}
}
}//end of method
}
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.function.Predicate;
import java.util.stream.Collectors;
public class Answers {
public static void main(String[] args) {
String input1 = "Hello! Are you all fine? What are u doing today? Hey Guyz,Listen! I have a plan for today.";
String[] arin = input1.split("");
Predicate<String> checkIfValidChar = str -> ((str.charAt(0) >= '0' && str.charAt(0) <= '9')
|| (str.charAt(0) >= 'a' && str.charAt(0) <= 'z')
|| (str.charAt(0) >= 'A' && str.charAt(0) <= 'Z'));
String maxChar = Arrays.stream(arin).max(Comparator.comparing(i -> Arrays.stream(arin).filter(j -> {
return i.equalsIgnoreCase(j) && checkIfValidChar.test(j);
}).count())).get();
int count = Collections.frequency(Arrays.asList(arin), maxChar);
System.out.println(Arrays.stream(arin).filter(i -> {
return Collections.frequency(Arrays.asList(arin), i) == count && checkIfValidChar.test(i);
}).collect(Collectors.toSet()));
}
}
I see many answers that are unnecessarily convoluted, import tons of stuff or use a cannon to shoot a mosquito ( the accepted answer uses an HashTable ).
Here a simple solution:
public List<Character> mostFrequentLetter(String message) {
var m = message
.replaceAll("[^a-z]", "")
.toLowerCase();
int[] count = new int[26];
for(var c : m.toCharArray()){
int i = ((int)c)-97;
count[i]++;
}
var max_i = 0; // index of the most frequent letter
var max_c = count[max_i]; // count of the most frequent letter
var max = new ArrayList<Character>(3); // list containing letters with the same frequency
for(int i = 1; i < 26; ++i){
if (count[i] >= max_c){
max_i = i;
char c = (char)(max_i + 97);
if(count[i]!=max_c){
max.clear();
max_c = count[i];
}
max.add(c);
}
}
return max;
}
Here str will be the given string. This is Javascript code
function maxCharacter(str){
let str1 = str; let reptCharsCount=0; let ele='';let maxCount=0;
let charArr = str1.split('');
for(let i=0; i< str1.length; i++){
reptCharsCount=0;
for(let j=0; j< str1.length; j++){
if(str1[i] === str1[j]) {
reptCharsCount++;
}
}
if(reptCharsCount > maxCount) {
ele = str1[i];
maxCount = reptCharsCount;
}
}
return ele;
}
Although all the answers are correct posting my way of doing it
/Question: For the given string such as "aabbbbbcc" print the longest occurring character,
index and number of times it occurs.
Ex:
"longest occurring character is b and length is 5 at index 2"./
class Codechef {
public static void main (String[] args) {
String problem = "aabbbbbcc";
Map<Character,Temp> map = new HashMap<>();
for(int i = 0; i < problem.length(); i++){
if (map.containsKey(problem.charAt(i))) {
map.get(problem.charAt(i)).incrementCount();
} else {
map.put(problem.charAt(i), new Temp(i, 1, problem.charAt(i)));
}
}
List<Map.Entry<Character, Temp>> listOfValue = new LinkedList<Map.Entry<Character, Temp>>(map.entrySet());
Comparator<Map.Entry<Character, Temp>> comp = (val1, val2) -> (val1.getValue().getCount() < val2.getValue().getCount() ? 1: -1);
Collections.sort(listOfValue, comp);
Temp tmp = listOfValue.get(0).getValue();
System.out.println("longest occurring character is "+ tmp.getStr()+ " and length is " + tmp.getCount()+ " at index "+ tmp.getIndex());
}}
And then created one Model class to keep these values
class Temp {
Integer index;
Integer count;
Character str;
public Temp(Integer index, Integer count, Character str ){
this.index = index;
this.count = count;
this.str = str;
}
public void incrementCount(){
this.count++;
}
public Integer getCount(){
return count;
}
public Character getStr(){
return str;
}
public Integer getIndex(){
return index;
}}
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
public class Maxchar {
public static void main(String[] args) {
String str = "vaquar khan.";
// System.out.println();
System.out.println(maxChar(str));
String testcase1 = "Hello! Are you all fine? What are u doing today? Hey Guyz,Listen! I have a plan for today.";
System.out.println(maxChar(testcase1));
}
private static char maxChar(String str) {
if (null == str)
return ' ';
char[] charArray = str.replaceAll("\s+", "").toCharArray();
//
Map<Character, Integer> maxcharmap = new HashMap<Character, Integer>();
//
for (char c : charArray) {
if (maxcharmap.containsKey(c)) {
maxcharmap.put(c, maxcharmap.get(c) + 1);
} else {
maxcharmap.put(c, 1);
}
// Inside map we have word count
// System.out.println(maxcharmap.toString());
}
//
//
Set<Entry<Character, Integer>> entrySet = maxcharmap.entrySet();
int count = 0;
char maxChar = 0;
//
for (Entry<Character, Integer> entry : entrySet) {
if (entry.getValue() > count) {
count = entry.getValue();
maxChar = entry.getKey();
}
}
System.out.println("Maximum Occurring char and its count :");
System.out.println(maxChar + " : " + count);
return maxChar;
}
}
If you're open to 3rd party libraries you could use the Bag type from Eclipse Collections and select the top occurrences.
public char[] maxOccurringChar(String s) {
MutableCharBag bag = CharBags.mutable.of(s.toCharArray());
MutableList<CharIntPair> maxOccurringCharsWithCounts = bag.topOccurrences(1);
MutableCharList maxOccurringChars = maxOccurringCharsWithCounts.collectChar(CharIntPair::getOne);
return maxOccurringChars.toArray();
}
Note in this example we used the primitive collections to avoid boxing of the char and int types.
import java.util.*;
import java.util.stream.*;
class MaxOccur{
public static void main(String[] args){
String str = "sfowfjalkfaeffawkefjweajjwjegjoweeowe";
maxOcc(str);
}
public static void maxOcc(String s){
ArrayList<Character> arr = (ArrayList<Character>) s.chars().mapToObj(e ->(char)e).collect(Collectors.toList());
HashSet<Character> hs = new HashSet<>(arr);
int max = 0;
int f = 0;
String answer = "";
for(Character ch : hs){
f = Collections.frequency(arr,ch);
if(f>max){
max = f;
answer = ch;
}
System.out.println(ch + " occurs " + max + " times, the maximum");
}
}
In above, I'm using streams. Following are the steps:
Converting string's characters to arraylist using streams.
Making a hashset (discards all duplicate occurences of characters) using the arrayList created in step 1.
Use Collections.frequency to count occurence of each character in arrayList.
It's not the easiest solution, neither is it really adorable! But, it makes use of streams, something which i recently started learning and wanted to apply. I'm no adept in using streams, but they are beautiful. I've learnt most of them here on stackoverflow, and i'm so grateful. :)
Map the chars to their occurrence then query entries for the max value and get its key, note this will return the first char that has the highest occurrence
"abc".chars().mapToObj(c -> (char) c)
.collect(Collectors.groupingBy(Function.identity(),Collectors.counting()))
.entrySet()
.stream()
.max(Comparator.comparingLong(Map.Entry::getValue))
.get()
.getKey();
Here I am posting the answer by using HashMap
public class maximumOccurrence {
public static Map<Character,Integer> maximumOccurence(String s) {
char maxchar='';
int maxint=0;
Map<Character,Integer> map = new HashMap<Character, Integer>();
char strAtt[]= s.toCharArray();
for(Character ch : strAtt) {
if(map.containsKey(ch)) {
map.put(ch, map.get(ch)+1);
}else {
map.put(ch,1);
}
}
for(Map.Entry<Character,Integer> entry : map.entrySet()) {
System.out.println(entry.getKey() + "/" + entry.getValue());
if(maxint<entry.getValue()) {
maxint=entry.getValue();
maxchar=entry.getKey();
}
}
System.out.println("Character repeated ="+maxchar+" it's value is:"+maxint);
return map;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
String s= "uuuiiiiiiiiiiioooooopp";
System.out.println(maximumOccurence(s));
}
}

Finding repeated words on a string and counting the repetitions

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, House, Dog, Dog, Dog, Dog";
I need to create a new string list without repetitions and save somewhere else the amount of repetitions for each word, like such:
New String: "House, Dog"
New Int Array: [3, 4]
Is there a way to do this easily with Java? I've managed to separate the string using s.split() but then how do I count repetitions and eliminate them on the new string? Thanks!
You've got the hard work done. Now you can just use a Map to count the occurrences:
Map<String, Integer> occurrences = new HashMap<String, Integer>();
for ( String word : splitWords ) {
Integer oldCount = occurrences.get(word);
if ( oldCount == null ) {
oldCount = 0;
}
occurrences.put(word, oldCount + 1);
}
Using map.get(word) will tell you many times a word occurred. You can construct a new list by iterating through map.keySet():
for ( String word : occurrences.keySet() ) {
//do something with word
}
Note that the order of what you get out of keySet is arbitrary. If you need the words to be sorted by when they first appear in your input String, you should use a LinkedHashMap instead.
Try this,
public class DuplicateWordSearcher {
#SuppressWarnings("unchecked")
public static void main(String[] args) {
String text = "a r b k c d se f g a d f s s f d s ft gh f ws w f v x s g h d h j j k f sd j e wed a d f";
List<String> list = Arrays.asList(text.split(" "));
Set<String> uniqueWords = new HashSet<String>(list);
for (String word : uniqueWords) {
System.out.println(word + ": " + Collections.frequency(list, word));
}
}
}
public class StringsCount{
public static void main(String args[]) {
String value = "This is testing Program testing Program";
String item[] = value.split(" ");
HashMap<String, Integer> map = new HashMap<>();
for (String t : item) {
if (map.containsKey(t)) {
map.put(t, map.get(t) + 1);
} else {
map.put(t, 1);
}
}
Set<String> keys = map.keySet();
for (String key : keys) {
System.out.println(key);
System.out.println(map.get(key));
}
}
}
As mentioned by others use String::split(), followed by some map (hashmap or linkedhashmap) and then merge your result. For completeness sake putting the code.
import java.util.*;
public class Genric<E>
{
public static void main(String[] args)
{
Map<String, Integer> unique = new LinkedHashMap<String, Integer>();
for (String string : "House, House, House, Dog, Dog, Dog, Dog".split(", ")) {
if(unique.get(string) == null)
unique.put(string, 1);
else
unique.put(string, unique.get(string) + 1);
}
String uniqueString = join(unique.keySet(), ", ");
List<Integer> value = new ArrayList<Integer>(unique.values());
System.out.println("Output = " + uniqueString);
System.out.println("Values = " + value);
}
public static String join(Collection<String> s, String delimiter) {
StringBuffer buffer = new StringBuffer();
Iterator<String> iter = s.iterator();
while (iter.hasNext()) {
buffer.append(iter.next());
if (iter.hasNext()) {
buffer.append(delimiter);
}
}
return buffer.toString();
}
}
New String is Output = House, Dog
Int array (or rather list) Values = [3, 4] (you can use List::toArray) for getting an array.
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]
If this is a homework, then all I can say is: use String.split() and HashMap<String,Integer>.
(I see you've found split() already. You're along the right lines then.)
It may help you somehow.
String st="I am am not the one who is thinking I one thing at time";
String []ar = st.split("\\s");
Map<String, Integer> mp= new HashMap<String, Integer>();
int count=0;
for(int i=0;i<ar.length;i++){
count=0;
for(int j=0;j<ar.length;j++){
if(ar[i].equals(ar[j])){
count++;
}
}
mp.put(ar[i], count);
}
System.out.println(mp);
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}
You can use Prefix tree (trie) data structure to store words and keep track of count of words within Prefix Tree Node.
#define ALPHABET_SIZE 26
// Structure of each node of prefix tree
struct prefix_tree_node {
prefix_tree_node() : count(0) {}
int count;
prefix_tree_node *child[ALPHABET_SIZE];
};
void insert_string_in_prefix_tree(string word)
{
prefix_tree_node *current = root;
for(unsigned int i=0;i<word.size();++i){
// Assuming it has only alphabetic lowercase characters
// Note ::::: Change this check or convert into lower case
const unsigned int letter = static_cast<int>(word[i] - 'a');
// Invalid alphabetic character, then continue
// Note :::: Change this condition depending on the scenario
if(letter > 26)
throw runtime_error("Invalid alphabetic character");
if(current->child[letter] == NULL)
current->child[letter] = new prefix_tree_node();
current = current->child[letter];
}
current->count++;
// Insert this string into Max Heap and sort them by counts
}
// Data structure for storing in Heap will be something like this
struct MaxHeapNode {
int count;
string word;
};
After inserting all words, you have to print word and count by iterating Maxheap.
//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");
}
}
public static void main(String[] args) {
String s="sdf sdfsdfsd sdfsdfsd sdfsdfsd sdf sdf sdf ";
String st[]=s.split(" ");
System.out.println(st.length);
Map<String, Integer> mp= new TreeMap<String, Integer>();
for(int i=0;i<st.length;i++){
Integer count=mp.get(st[i]);
if(count == null){
count=0;
}
mp.put(st[i],++count);
}
System.out.println(mp.size());
System.out.println(mp.get("sdfsdfsd"));
}
If you pass a String argument it will count the repetition of each word
/**
* #param string
* #return map which contain the word and value as the no of repatation
*/
public Map findDuplicateString(String str) {
String[] stringArrays = str.split(" ");
Map<String, Integer> map = new HashMap<String, Integer>();
Set<String> words = new HashSet<String>(Arrays.asList(stringArrays));
int count = 0;
for (String word : words) {
for (String temp : stringArrays) {
if (word.equals(temp)) {
++count;
}
}
map.put(word, count);
count = 0;
}
return map;
}
output:
Word1=2, word2=4, word2=1,. . .
import java.util.HashMap;
import java.util.LinkedHashMap;
public class CountRepeatedWords {
public static void main(String[] args) {
countRepeatedWords("Note that the order of what you get out of keySet is arbitrary. If you need the words to be sorted by when they first appear in your input String, you should use a LinkedHashMap instead.");
}
public static void countRepeatedWords(String wordToFind) {
String[] words = wordToFind.split(" ");
HashMap<String, Integer> wordMap = new LinkedHashMap<String, Integer>();
for (String word : words) {
wordMap.put(word,
(wordMap.get(word) == null ? 1 : (wordMap.get(word) + 1)));
}
System.out.println(wordMap);
}
}
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());
}
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class DuplicateWord {
public static void main(String[] args) {
String para = "this is what it is this is what it can be";
List < String > paraList = new ArrayList < String > ();
paraList = Arrays.asList(para.split(" "));
System.out.println(paraList);
int size = paraList.size();
int i = 0;
Map < String, Integer > duplicatCountMap = new HashMap < String, Integer > ();
for (int j = 0; size > j; j++) {
int count = 0;
for (i = 0; size > i; i++) {
if (paraList.get(j).equals(paraList.get(i))) {
count++;
duplicatCountMap.put(paraList.get(j), count);
}
}
}
System.out.println(duplicatCountMap);
List < Integer > myCountList = new ArrayList < > ();
Set < String > myValueSet = new HashSet < > ();
for (Map.Entry < String, Integer > entry: duplicatCountMap.entrySet()) {
myCountList.add(entry.getValue());
myValueSet.add(entry.getKey());
}
System.out.println(myCountList);
System.out.println(myValueSet);
}
}
Input: this is what it is this is what it can be
Output:
[this, is, what, it, is, this, is, what, it, can, be]
{can=1, what=2, be=1, this=2, is=3, it=2}
[1, 2, 1, 2, 3, 2]
[can, what, be, this, is, it]
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);
}
}
Please use the below code. It is the most simplest as per my analysis. Hope you will like it:
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;
import java.util.Set;
public class MostRepeatingWord {
String mostRepeatedWord(String s){
String[] splitted = s.split(" ");
List<String> listString = Arrays.asList(splitted);
Set<String> setString = new HashSet<String>(listString);
int count = 0;
int maxCount = 1;
String maxRepeated = null;
for(String inp: setString){
count = Collections.frequency(listString, inp);
if(count > maxCount){
maxCount = count;
maxRepeated = inp;
}
}
return maxRepeated;
}
public static void main(String[] args)
{
System.out.println("Enter The Sentence: ");
Scanner s = new Scanner(System.in);
String input = s.nextLine();
MostRepeatingWord mrw = new MostRepeatingWord();
System.out.println("Most repeated word is: " + mrw.mostRepeatedWord(input));
}
}
package day2;
import java.util.ArrayList;
import java.util.HashMap;`enter code here`
import java.util.List;
public class DuplicateWords {
public static void main(String[] args) {
String S1 = "House, House, House, Dog, Dog, Dog, Dog";
String S2 = S1.toLowerCase();
String[] S3 = S2.split("\\s");
List<String> a1 = new ArrayList<String>();
HashMap<String, Integer> hm = new HashMap<>();
for (int i = 0; i < S3.length - 1; i++) {
if(!a1.contains(S3[i]))
{
a1.add(S3[i]);
}
else
{
continue;
}
int Count = 0;
for (int j = 0; j < S3.length - 1; j++)
{
if(S3[j].equals(S3[i]))
{
Count++;
}
}
hm.put(S3[i], Count);
}
System.out.println("Duplicate Words and their number of occurrences in String S1 : " + hm);
}
}
public class Counter {
private static final int COMMA_AND_SPACE_PLACE = 2;
private String mTextToCount;
private ArrayList<String> mSeparateWordsList;
public Counter(String mTextToCount) {
this.mTextToCount = mTextToCount;
mSeparateWordsList = cutStringIntoSeparateWords(mTextToCount);
}
private ArrayList<String> cutStringIntoSeparateWords(String text)
{
ArrayList<String> returnedArrayList = new ArrayList<>();
if(text.indexOf(',') == -1)
{
returnedArrayList.add(text);
return returnedArrayList;
}
int position1 = 0;
int position2 = 0;
while(position2 < text.length())
{
char c = ',';
if(text.toCharArray()[position2] == c)
{
String tmp = text.substring(position1, position2);
position1 += tmp.length() + COMMA_AND_SPACE_PLACE;
returnedArrayList.add(tmp);
}
position2++;
}
if(position1 < position2)
{
returnedArrayList.add(text.substring(position1, position2));
}
return returnedArrayList;
}
public int[] countWords()
{
if(mSeparateWordsList == null) return null;
HashMap<String, Integer> wordsMap = new HashMap<>();
for(String s: mSeparateWordsList)
{
int cnt;
if(wordsMap.containsKey(s))
{
cnt = wordsMap.get(s);
cnt++;
} else {
cnt = 1;
}
wordsMap.put(s, cnt);
}
return printCounterResults(wordsMap);
}
private int[] printCounterResults(HashMap<String, Integer> m)
{
int index = 0;
int[] returnedIntArray = new int[m.size()];
for(int i: m.values())
{
returnedIntArray[index] = i;
index++;
}
return returnedIntArray;
}
}
/*count no of Word in String using TreeMap we can use HashMap also but word will not display in sorted order */
import java.util.*;
public class Genric3
{
public static void main(String[] args)
{
Map<String, Integer> unique = new TreeMap<String, Integer>();
String string1="Ram:Ram: Dog: Dog: Dog: Dog:leela:leela:house:house:shayam";
String string2[]=string1.split(":");
for (int i=0; i<string2.length; i++)
{
String string=string2[i];
unique.put(string,(unique.get(string) == null?1:(unique.get(string)+1)));
}
System.out.println(unique);
}
}
//program to find number of repeating characters in a string
//Developed by Rahul Lakhmara
import java.util.*;
public class CountWordsInString {
public static void main(String[] args) {
String original = "I am rahul am i sunil so i can say am i";
// making String type of array
String[] originalSplit = original.split(" ");
// if word has only one occurrence
int count = 1;
// LinkedHashMap will store the word as key and number of occurrence as
// value
Map<String, Integer> wordMap = new LinkedHashMap<String, Integer>();
for (int i = 0; i < originalSplit.length - 1; i++) {
for (int j = i + 1; j < originalSplit.length; j++) {
if (originalSplit[i].equals(originalSplit[j])) {
// Increment in count, it will count how many time word
// occurred
count++;
}
}
// if word is already present so we will not add in Map
if (wordMap.containsKey(originalSplit[i])) {
count = 1;
} else {
wordMap.put(originalSplit[i], count);
count = 1;
}
}
Set word = wordMap.entrySet();
Iterator itr = word.iterator();
while (itr.hasNext()) {
Map.Entry map = (Map.Entry) itr.next();
// Printing
System.out.println(map.getKey() + " " + map.getValue());
}
}
}
public static void main(String[] args){
String string = "elamparuthi, elam, elamparuthi";
String[] s = string.replace(" ", "").split(",");
String[] op;
String ops = "";
for(int i=0; i<=s.length-1; i++){
if(!ops.contains(s[i]+"")){
if(ops != "")ops+=", ";
ops+=s[i];
}
}
System.out.println(ops);
}
For Strings with no space, we can use the below mentioned code
private static void findRecurrence(String input) {
final Map<String, Integer> map = new LinkedHashMap<>();
for(int i=0; i<input.length(); ) {
int pointer = i;
int startPointer = i;
boolean pointerHasIncreased = false;
for(int j=0; j<startPointer; j++){
if(pointer<input.length() && input.charAt(j)==input.charAt(pointer) && input.charAt(j)!=32){
pointer++;
pointerHasIncreased = true;
}else{
if(pointerHasIncreased){
break;
}
}
}
if(pointer - startPointer >= 2) {
String word = input.substring(startPointer, pointer);
if(map.containsKey(word)){
map.put(word, map.get(word)+1);
}else{
map.put(word, 1);
}
i=pointer;
}else{
i++;
}
}
for(Map.Entry<String, Integer> entry : map.entrySet()){
System.out.println(entry.getKey() + " = " + (entry.getValue()+1));
}
}
Passing some input as "hahaha" or "ba na na" or "xxxyyyzzzxxxzzz" give the desired output.
Hope this helps :
public static int countOfStringInAText(String stringToBeSearched, String masterString){
int count = 0;
while (masterString.indexOf(stringToBeSearched)>=0){
count = count + 1;
masterString = masterString.substring(masterString.indexOf(stringToBeSearched)+1);
}
return count;
}
package string;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
public class DublicatewordinanArray {
public static void main(String[] args) {
String str = "This is Dileep Dileep Kumar Verma Verma";
DuplicateString(str);
}
public static void DuplicateString(String str) {
String word[] = str.split(" ");
Map < String, Integer > map = new HashMap < String, Integer > ();
for (String w: word)
if (!map.containsKey(w)) {
map.put(w, 1);
}
else {
map.put(w, map.get(w) + 1);
}
Set < Map.Entry < String, Integer >> entrySet = map.entrySet();
for (Map.Entry < String, Integer > entry: entrySet)
if (entry.getValue() > 1) {
System.out.printf("%s : %d %n", entry.getKey(), entry.getValue());
}
}
}
Using Java 8 streams collectors:
public static Map<String, Integer> countRepetitions(String str) {
return Arrays.stream(str.split(", "))
.collect(Collectors.toMap(s -> s, s -> 1, (a, b) -> a + 1));
}
Input: "House, House, House, Dog, Dog, Dog, Dog, Cat"
Output: {Cat=1, House=3, Dog=4}
please try these it may be help for you.
public static void main(String[] args) {
String str1="House, House, House, Dog, Dog, Dog, Dog";
String str2=str1.replace(",", "");
Map<String,Integer> map=findFrquenciesInString(str2);
Set<String> keys=map.keySet();
Collection<Integer> vals=map.values();
System.out.println(keys);
System.out.println(vals);
}
private static Map<String,Integer> findFrquenciesInString(String str1) {
String[] strArr=str1.split(" ");
Map<String,Integer> map=new HashMap<>();
for(int i=0;i<strArr.length;i++) {
int count=1;
for(int j=i+1;j<strArr.length;j++) {
if(strArr[i].equals(strArr[j]) && strArr[i]!="-1") {
strArr[j]="-1";
count++;
}
}
if(count>1 && strArr[i]!="-1") {
map.put(strArr[i], count);
strArr[i]="-1";
}
}
return map;
}
as introduction of stream has changed the way we code; i would like to add some of the ways of doing this using it
String[] strArray = str.split(" ");
//1. All string value with their occurrences
Map<String, Long> counterMap =
Arrays.stream(strArray).collect(Collectors.groupingBy(e->e, Collectors.counting()));
//2. only duplicating Strings
Map<String, Long> temp = counterMap.entrySet().stream().filter(map->map.getValue() > 1).collect(Collectors.toMap(map -> map.getKey(), map -> map.getValue()));
System.out.println("test : "+temp);
//3. List of Duplicating Strings
List<String> masterStrings = Arrays.asList(strArray);
Set<String> duplicatingStrings =
masterStrings.stream().filter(i -> Collections.frequency(masterStrings, i) > 1).collect(Collectors.toSet());
Use Function.identity() inside Collectors.groupingBy and store everything in a MAP.
String a = "Gini Gina Gina Gina Gina Protijayi Protijayi ";
Map<String, Long> map11 = Arrays.stream(a.split(" ")).collect(Collectors
.groupingBy(Function.identity(),Collectors.counting()));
System.out.println(map11);
// output => {Gina=4, Gini=1, Protijayi=2}
In Python we can use collections.Counter()
a = "Roopa Roopi loves green color Roopa Roopi"
words = a.split()
wordsCount = collections.Counter(words)
for word,count in sorted(wordsCount.items()):
print('"%s" is repeated %d time%s.' % (word,count,"s" if count > 1 else "" ))
Output :
"Roopa" is repeated 2 times.
"Roopi" is repeated 2 times.
"color" is repeated 1 time.
"green" is repeated 1 time.
"loves" is repeated 1 time.

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