This is a java program to solve approximate string matching using dynamic programming.
Here is the source code of the Java Program to Use Dynamic Programming to Solve Approximate String Matching. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.
package com.maixuanviet.setandstring; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Scanner; public class ApproxStringMatching { private List<String> foods = new ArrayList<String>(); private Map<String, Double> matchingScores = new HashMap<String, Double>(); private Scanner scanner; private static double[][] mismatchScoreTable; private String in; private int inLength; public ApproxStringMatching(String text) { /* * read the file, fill the food list */ try { scanner = new Scanner(text); while (scanner.hasNext()) { this.foods.add(scanner.nextLine()); } } catch (Exception e) { e.printStackTrace(); System.exit(1); } if (mismatchScoreTable == null) initMismatchScoreTable(); } public List<String> getFoods() { return this.foods; } private static void initMismatchScoreTable() { mismatchScoreTable = new double[256][256]; /* * Score any combination of two characters as 1 by default. */ for (int i = 0; i < 256; i++) for (int j = 0; j < 256; j++) mismatchScoreTable[i][j] = 1.0d; /* * If the input charater and reference character are the same, * there is no typo. So the error score is 0. */ for (int i = 0; i < 256; i++) mismatchScoreTable[i][i] = 0.0d; /* * For people who use both German keyboard and English keyboard, * this typo is highly frequent. */ mismatchScoreTable['y']['z'] = 0.1d; mismatchScoreTable['z']['y'] = 0.1d; mismatchScoreTable['v']['b'] = 0.15d; mismatchScoreTable['b']['v'] = 0.15d; mismatchScoreTable['n']['m'] = 0.11d; mismatchScoreTable['m']['n'] = 0.11d; mismatchScoreTable['t']['r'] = 0.15d; mismatchScoreTable['r']['t'] = 0.15d; mismatchScoreTable['g']['h'] = 0.15d; mismatchScoreTable['h']['g'] = 0.15d; mismatchScoreTable['y']['u'] = 0.15d; mismatchScoreTable['u']['y'] = 0.15d; /* * more typo possibilities can be inserted here.... */ } public Map<String, Double> getScores(String in) { this.in = in; this.inLength = in.length(); for (String food : this.foods) { int refLength = food.length(); double[][] errScore = new double[inLength + 1][refLength + 1]; errScore[0][0] = 0.0d; for (int inCharAt = 1; inCharAt <= this.inLength; inCharAt++) errScore[inCharAt][0] = inCharAt; for (int refCharAt = 1; refCharAt <= refLength; refCharAt++) errScore[0][refCharAt] = refCharAt; for (int inCharAt = 1; inCharAt <= inLength; inCharAt++) for (int refCharAt = 1; refCharAt <= refLength; refCharAt++) { /* * if a character is absent at the given position * in the input string, we add score 1. */ double charAbsence = errScore[inCharAt - 1][refCharAt] + 1; /* * if a character is redundant at the given position in the * input string, we add score 1. */ double charRedundance = errScore[inCharAt][refCharAt - 1] + 1; /* * if it is a matching error, we add the score specified in * the score table for matching errors. */ double mismatch = errScore[inCharAt - 1][refCharAt - 1] + mismatchScoreTable[this.in.charAt(inCharAt - 1)][food .charAt(refCharAt - 1)]; /* * initialize the score for swap error to a very big value. */ double charPositionSwap = 999999d; /* * score for swap error */ if (inCharAt > 1 && refCharAt > 1 && this.in.charAt(inCharAt - 1) == food .charAt(refCharAt - 2) && this.in.charAt(inCharAt - 2) == food .charAt(refCharAt - 1)) { /* * the score for typing "ie" as "ei" and vice versa * is even lower */ if (this.in.charAt(inCharAt - 2) == 'e' && this.in.charAt(inCharAt - 1) == 'i') { charPositionSwap = errScore[inCharAt - 2][refCharAt - 2] + 0.25; } /* * more cases can be inserted here. */ else charPositionSwap = errScore[inCharAt - 2][refCharAt - 2] + 0.5; } /* * more error cases can be inserted here. */ double minScore = mismatch; if (charAbsence < minScore) { minScore = charAbsence; } if (charRedundance < minScore) { minScore = charRedundance; } if (charPositionSwap < minScore) { minScore = charPositionSwap; } errScore[inCharAt][refCharAt] = minScore; } this.matchingScores.put(food, errScore[this.inLength][refLength]); } return this.matchingScores; } @SuppressWarnings({ "unchecked", "rawtypes" }) public static void main(String[] args) { String text = "In computer science, approximate string matching " + "(often colloquially referred to as fuzzy string searching) is the technique of finding strings that match a pattern approximately (rather than exactly). " + "The problem of approximate string matching is typically divided into two sub-problems: finding approximate substring matches inside a given string and finding " + "dictionary strings that match the pattern approximately."; Scanner sc = new Scanner(System.in); ApproxStringMatching demo = new ApproxStringMatching(text); System.out.print("Please type a word. Type q for exit: "); sc.nextLine(); while (sc.hasNext()) { String in = sc.nextLine(); if (in.equals("q")) { System.exit(0); } System.out.println("You typed " + in); System.out.println("--------------------------------------------"); Map scoreMap = demo.getScores(in); for (String food : demo.getFoods()) { System.out.println(food + "\t error score: " + scoreMap.get(food)); } System.out.println("--------------------------------------------"); double minScore = (Double) Collections.min(scoreMap.values()); if (minScore == 0.0d) { System.out.println(in + " is in the list."); } else { List<String> corrections = new ArrayList<String>(); StringBuffer sb = new StringBuffer("Do you mean:- "); for (String food : demo.getFoods()) { if (scoreMap.get(food).equals(minScore)) { corrections.add(food); sb.append(food).append(" or "); } } sb.append("?"); System.out.println(sb.toString()); } System.out.println("Please type a word. Type q for exit: "); } sc.close(); } }
Output:
$ javac ApproxStringMatching.java $ java ApproxStringMatching Please type a word. Type q for exit: String You typed String -------------------------------------------- In computer science, approximate string matching (often colloquially referred to as fuzzy string searching) is the technique of finding strings that match a pattern approximately (rather than exactly). The problem of approximate string matching is typically divided into two sub-problems: finding approximate substring matches inside a given string and finding dictionary strings that match the pattern approximately. error score: 417.0 -------------------------------------------- Do you mean:- In computer science, approximate string matching (often colloquially referred to as fuzzy string searching) is the technique of finding strings that match a pattern approximately (rather than exactly). The problem of approximate string matching is typically divided into two sub-problems: finding approximate substring matches inside a given string and finding dictionary strings that match the pattern approximately. or ? Please type a word. Type q for exit: Matching You typed Matching -------------------------------------------- In computer science, approximate string matching (often colloquially referred to as fuzzy string searching) is the technique of finding strings that match a pattern approximately (rather than exactly). The problem of approximate string matching is typically divided into two sub-problems: finding approximate substring matches inside a given string and finding dictionary strings that match the pattern approximately. error score: 410.0 -------------------------------------------- Do you mean:- In computer science, approximate string matching (often colloquially referred to as fuzzy string searching) is the technique of finding strings that match a pattern approximately (rather than exactly). The problem of approximate string matching is typically divided into two sub-problems: finding approximate substring matches inside a given string and finding dictionary strings that match the pattern approximately. or ? Please type a word. Type q for exit:
Related posts:
Giới thiệu Google Guice – Dependency injection (DI) framework
Debug a JavaMail Program
Java Byte Array to InputStream
Rate Limiting in Spring Cloud Netflix Zuul
Spring Security Authentication Provider
Java Program to implement Priority Queue
HttpClient Timeout
Adding Shutdown Hooks for JVM Applications
How to Get a Name of a Method Being Executed?
Java Program to Implement Range Tree
The Basics of Java Security
Java Program to Implement PriorityQueue API
Immutable Map Implementations in Java
Java Program to Implement ArrayDeque API
Introduction to the Java ArrayDeque
How to Get All Dates Between Two Dates?
Lớp lồng nhau trong java (Java inner class)
Practical Java Examples of the Big O Notation
Java Program to Find Number of Spanning Trees in a Complete Bipartite Graph
Spring Cloud Connectors and Heroku
Java Program to Implement Depth-limited Search
Jackson – Decide What Fields Get Serialized/Deserialized
Lập trình đa luồng trong Java (Java Multi-threading)
Java Program to Find Hamiltonian Cycle in an UnWeighted Graph
Running Spring Boot Applications With Minikube
A Guide to LinkedHashMap in Java
Life Cycle of a Thread in Java
A Guide to TreeSet in Java
Java Program to Perform the Unique Factorization of a Given Number
Quick Guide to the Java StringTokenizer
Java Program to Implement the Program Used in grep/egrep/fgrep
Java Program to Implement Borwein Algorithm