Nodejs Distance Calculate getEditDistance(a, b)

Method Source Code

// Compute the edit distance between the two given strings
function getEditDistance(a, b){
  if(a.length == 0) return b.length;
  if(b.length == 0) return a.length;

  var matrix = [];

  // increment along the first column of each row
  var i;//from   w w w.j  ava 2 s .c om
  for(i = 0; i <= b.length; i++){
    matrix[i] = [i];
  }

  // increment each column in the first row
  var j;
  for(j = 0; j <= a.length; j++){
    matrix[0][j] = j;
  }

  // Fill in the rest of the matrix
  for(i = 1; i <= b.length; i++){
    for(j = 1; j <= a.length; j++){
      if(b.charAt(i-1) == a.charAt(j-1)){
        matrix[i][j] = matrix[i-1][j-1];
      } else {
        matrix[i][j] = Math.min(matrix[i-1][j-1] + 1, // substitution
                                Math.min(matrix[i][j-1] + 1, // insertion
                                         matrix[i-1][j] + 1)); // deletion
      }
    }
  }

  return matrix[b.length][a.length];
};

Array.prototype.contains = function(obj) {
  for (var i = 0; i < this.length; i++) {
    if (this[i] === obj) {
      return true;
    }
  }
  return false;
}

Related

1. distance(lat1,lon1,lat2,lon2)

   function distance(lat1,lon1,lat2,lon2) {
     var R = 6371; 
     var dLat = deg2rad(lat2-lat1);  
     var dLon = deg2rad(lon2-lon1);
     var a =
       Math.sin(dLat/2) * Math.sin(dLat/2) +
       Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) *
       Math.sin(dLon/2) * Math.sin(dLon/2)
       ;
   ...
   

2. distance(p1, p2)

   function Point(x, y) {
       this.x = x;
       this.y = y;
   function randomPoint() {
       var randomx = randomNumber(WIDTH);
       var randomy = randomNumber(HEIGHT);
       var randomPoint = new Point(randomx, randomy);
       return randomPoint;
   ...
   

3. distance(x1, x2, y1, y2)

   Math.distance = function(x1, x2, y1, y2){
     var x = x2 - x1;
     var y = y2 - y1;
     return Math.sqrt(x * x + y * y);
   };
   

4. distanceBetweenTwoPoints(p1, p2)

   Util.distanceBetweenTwoPoints = function(p1, p2) {
     return Math.sqrt(Math.pow(p2.y - p1.y, 2) + Math.pow(p2.x - p1.x, 2)).toFixed(2);
   };
   

5. distanceOfTimeInWords(from, to)

   window.distanceOfTimeInWords = function (from, to) {
     var distance_in_milliseconds = to - from;
     var distance_in_minutes = Math.round(Math.abs(distance_in_milliseconds / 60000));
     var words = "";
     if (distance_in_minutes == 0) {
       words = "less than a minute";
     } else if (distance_in_minutes == 1) {
       words = "1 minute";
     } else if (distance_in_minutes < 45) {
   ...
   

6. get_distance (lat1, lon1, lat2, lon2)

   function get_distance (lat1, lon1, lat2, lon2) {
     var R = 6371;
     var dLat = deg2rad(lat2-lat1);
     var dLon = deg2rad(lon2-lon1);
     var lat1 = deg2rad(lat1);
     var lat2 = deg2rad(lat2);
     var a = Math.sin(dLat/2) * Math.sin(dLat/2) +
             Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2); 
     var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
   ...
   

7. haversineDistance(lat1, lng1, lat2, lng2)

   var haversineDistance(lat1, lng1, lat2, lng2) {
       var R = 6371; 
       var deltaLat = (lat2-lat1).inRadians();
       var deltaLng = (lng2-lng1).inRadians();
       var a = (Math.sin(deltaLat/2) * Math.sin(deltaLat/2)) + (Math.cos(lat1.inRadians()) * Math.cos(lat2.inRadians()) *
                      Math.sin(deltaLng/2) * Math.sin(deltaLng/2));
       var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
       return R * c; 
   

8. haversineDistance(lat1, lon1, lat2, lon2)

   function haversineDistance(lat1, lon1, lat2, lon2){
     var R = 6371; 
     var x1 = lat2-lat1;
     var dLat = x1.toRad();  
     var x2 = lon2-lon1;
     var dLon = x2.toRad();  
     var a = Math.sin(dLat/2) * Math.sin(dLat/2) + 
     Math.cos(lat1.toRad()) * Math.cos(lat2.toRad()) * 
     Math.sin(dLon/2) * Math.sin(dLon/2);  
   ...