Is the PHP levenshtein() function buggy?

Question

On this page levenshtein(), I am using the example #1 with following variables:

// input misspelled word
$input = 'htc corporation';

// array of words to check against
$words = array('htc', 'Sprint Nextel', 'Sprint', 'banana', 'orange',
        'radish', 'carrot', 'pea', 'bean');

Could someone please tell me why the expected result is carrot rather than htc? Thanks

Answer 1

Levenshtein distance is a string metric for measuring the difference between two sequences. Informally, the Levenshtein distance between two words is the minimum number of single-character edits (insertion, deletion, substitution) required to change one word into the other.

here is a simple analysis

$input = 'htc corporation';

// array of words to check against
$words = array(
    'htc',
    'Sprint Nextel',
    'Sprint',
    'banana',
    'orange',
    'radish',
    'carrot',
    'pea',
    'bean' 
);

foreach ( $words as $word ) {

    // Check for Intercept
    $ic = array_intersect(str_split($input), str_split($word));

    printf("%s \t l= %s , s = %s , c = %d \n",$word ,  
    levenshtein($input, $word), 
    similar_text($input, $word), 
    count($ic));
}

Output

htc      l= 12 , s = 3 , c = 5 
Sprint Nextel    l= 14 , s = 3 , c = 8 
Sprint   l= 12 , s = 1 , c = 7 
banana   l= 14 , s = 2 , c = 2 
orange   l= 12 , s = 4 , c = 7 
radish   l= 12 , s = 3 , c = 5 
carrot   l= 11 , s = 1 , c = 10  
pea      l= 13 , s = 2 , c = 2 
bean     l= 13 , s = 2 , c = 2 

It clear htc has a distance of 12 while carrot has 11 if you want htc then Levenshtein alone is not enough .. you need to compare exact word then set priorities