In this Java tutorial, you will learn How to Find Maximum Occurrence of Words from given Text File?
Here is a logic for getting top element:
- Create a class
CrunchifyComparablethat can store the String value of the word and the number of occurrences it appears. - Implement the
Comparable interfacefor this class tosort by occurrences first and then alphabeticallyif the number of occurrences is the same crunchifyFindMaxOccurancemethod, you create a new List ofCrunchifyComparablefrom your original map. You add the entries of this to your List- Sort this list
- Take the n-first items of this list using subList
- Add Strings to the
List<String>and you return it
Another most read: Find more information on equals() and hashcode()
Java Code:
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package crunchify.com.tutorial; import java.io.BufferedReader; import java.io.File; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Map.Entry; import java.util.Set; public class CrunchifyFindMaxOccurance { /** * @author Crunchify.com */ public static void main(String[] args) throws FileNotFoundException, IOException { File file = new File("/Users/<username>/Documents/test.txt"); BufferedReader bufferedReader = null; bufferedReader = new BufferedReader(new FileReader(file)); String inputLine = null; Map<String, Integer> crunchifyMap = new HashMap<>(); try { while ((inputLine = bufferedReader.readLine()) != null) { String[] words = inputLine.split("[ \n\t\r.,;:!?(){}]"); for (int counter = 0; counter < words.length; counter++) { String key = words[counter].toLowerCase(); // remove .toLowerCase for Case Sensitive result. if (key.length() > 0) { if (crunchifyMap.get(key) == null) { crunchifyMap.put(key, 1); } else { int value = crunchifyMap.get(key).intValue(); value++; crunchifyMap.put(key, value); } } } } Set<Map.Entry<String, Integer>> entrySet = crunchifyMap.entrySet(); System.out.println("Words" + "\t\t" + "# of Occurances"); for (Map.Entry<String, Integer> entry : entrySet) { System.out.println(entry.getKey() + "\t\t" + entry.getValue()); } List<String> myTopOccurrence = crunchifyFindMaxOccurance(crunchifyMap, 1); System.out.println("\nMaixmum Occurance of Word in file: "); for (String result : myTopOccurrence) { System.out.println("==> " + result); } } catch (IOException error) { System.out.println("Invalid File"); } finally { bufferedReader.close(); } } /** * @param map * = All Words in map * @param n * = How many top elements you want to print? If n=1 it will print highest occurrence word. If n=2 it * will print top 2 highest occurrence words. * @returns list of String */ public static List<String> crunchifyFindMaxOccurance(Map<String, Integer> map, int n) { List<CrunchifyComparable> l = new ArrayList<>(); for (Map.Entry<String, Integer> entry : map.entrySet()) l.add(new CrunchifyComparable(entry.getKey(), entry.getValue())); Collections.sort(l); List<String> list = new ArrayList<>(); for (CrunchifyComparable w : l.subList(0, n)) list.add(w.wordFromFile + ":" + w.numberOfOccurrence); return list; } } class CrunchifyComparable implements Comparable<CrunchifyComparable> { public String wordFromFile; public int numberOfOccurrence; public CrunchifyComparable(String wordFromFile, int numberOfOccurrence) { super(); this.wordFromFile = wordFromFile; this.numberOfOccurrence = numberOfOccurrence; } @Override public int compareTo(CrunchifyComparable arg0) { int crunchifyCompare = Integer.compare(arg0.numberOfOccurrence, this.numberOfOccurrence); return crunchifyCompare != 0 ? crunchifyCompare : wordFromFile.compareTo(arg0.wordFromFile); } @Override public int hashCode() { final int uniqueNumber = 19; int crunchifyResult = 9; crunchifyResult = uniqueNumber * crunchifyResult + numberOfOccurrence; crunchifyResult = uniqueNumber * crunchifyResult + ((wordFromFile == null) ? 0 : wordFromFile.hashCode()); return crunchifyResult; } @Override public boolean equals(Object crunchifyObj) { if (this == crunchifyObj) return true; if (crunchifyObj == null) return false; if (getClass() != crunchifyObj.getClass()) return false; CrunchifyComparable other = (CrunchifyComparable) crunchifyObj; if (numberOfOccurrence != other.numberOfOccurrence) return false; if (wordFromFile == null) { if (other.wordFromFile != null) return false; } else if (!wordFromFile.equals(other.wordFromFile)) return false; return true; } } |
Example1 file:
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This is test This is test This is test This is test This is test This is test This is test This is test This test This |
Output:
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1 2 3 4 5 6 7 |
Words # of Occurances test 9 this 10 is 8 Maixmum Occurance of Word in file: ==> this:10 |
Example2 File:
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1 |
this and and and then and this |
Output:
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1 2 3 4 5 6 7 |
Words # of Occurances and 4 this 2 then 1 Maixmum Occurance of Word in file: ==> and:4 |
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This does not work for input “this and and and then and this”. Reports “this” having max occurrence with count 2. Treemap sorts by keys, not values.