możesz użyć funkcji damerau-levenstein, aby uzyskać odległość między dwiema strunami. (Sprawdza to również transpozycję)
http://en.wikipedia.org/wiki/Damerau%E2%80 %93Levenshtein_distance
Jeśli twoje tabele są duże, być może będziesz musiał nieco zoptymalizować algorytm, aby się zepsuł, gdy odległość ciągu przekroczy próg.
Również jeśli możesz założyć, że pierwsza litera miasta jest wpisana poprawnie, powinno to zmniejszyć liczbę porównań do.
To nie jest PHP, ale jeśli jest jakaś pomoc, oto wersja java, którą napisałem:
class LevinshteinDistance{
public static void main(String args[]){
if(args.length != 2){
System.out.println("Displays the Levenshtein distance between 2 strings");
System.out.println("Usage: LevenshteinDistance stringA stringB");
}else{
int distance = getLevenshteinDistance(args[0], args[1]);
System.out.print(getLevenshteinMatrix(args[0], args[1]));
System.out.println("Distance: "+distance);
}
}
/**
* @param a first string for comparison
* @param b second string for comparison
* @param caseSensitive whether or not to use case sensitive matching
* @return a levenshtein string distance
*/
public static int getLevenshteinDistance(String a, String b, boolean caseSensitive){
if(! caseSensitive){
a = a.toUpperCase();
b = b.toUpperCase();
}
int[][] matrix = generateLevenshteinMatrix(a, b);
return matrix[a.length()][b.length()];
}
/**
* @param a first string for comparison
* @param b second string for comparison
* @return a case sensitive levenshtein string distance
*/
public static int getLevenshteinDistance(String a, String b){
int[][] matrix = generateLevenshteinMatrix(a, b);
return matrix[a.length()][b.length()];
}
/**
* @param a first string for comparison
* @param b second string for comparison
* @return a case sensitive string representation of the search matrix
*/
public static String getLevenshteinMatrix(String a, String b){
int[][] matrix = generateLevenshteinMatrix(a, b);
StringBuilder result = new StringBuilder();
final int ROWS = a.length()+1;
final int COLS = b.length()+1;
result.append(rowSeperator(COLS-1, false));
result.append("| "+b+" |\n");
result.append(rowSeperator(COLS-1, true));
for(int r=0; r<ROWS; r++){
result.append('|');
if(r > 0){
result.append(a.charAt(r-1));
}else{
result.append(' ');
}
result.append(" |");
for(int c=0; c<COLS; c++){
result.append(matrix[r][c]);
}
result.append(" |\n");
}
result.append(rowSeperator(COLS-1, false));
return result.toString();
}
private static String rowSeperator(final int LEN, boolean hasGap){
StringBuilder result = new StringBuilder();
if(hasGap){
result.append("+ +-");
}else{
result.append("+----");
}
for(int i=0; i<LEN; i++)
result.append('-');
result.append("-+\n");
return result.toString();
}
private static int[][] generateLevenshteinMatrix(String a, String b){
final int ROWS = a.length()+1;
final int COLS = b.length()+1;
int matrix[][] = new int[ROWS][COLS];
for(int r=0; r<ROWS; r++){
matrix[r][0]=r;
}
for(int c=0; c<COLS; c++){
matrix[0][c]=c;
}
for(int r=1; r<ROWS; r++){
char cA = a.charAt(r-1);
for(int c=1; c<COLS; c++){
char cB = b.charAt(c-1);
int cost = (cA == cB)?0:1;
int deletion = matrix[r-1][c]+1;
int insertion = matrix[r][c-1]+1;
int substitution = matrix[r-1][c-1]+cost;
int minimum = Math.min(Math.min(deletion, insertion), substitution);
if( (r > 1 && c > 1) && a.charAt(r-2) == cB && cA == b.charAt(c-2) ){
int transposition = matrix[r-2][c-2]+cost;
minimum = Math.min(minimum, transposition);
}
matrix[r][c] = minimum;
}
}
return matrix;
}
}