Hello,

How do we search for similar words in a string

for example:

string: "My lake is running out of water while I am watering the garden. Walter, did you hear me?"

if the key word is 'water', the results would return the words:

water
watering
Wa


I am stuck on this

Thanks.

"water" would not return Wa. Only if you were searching on "wa" and it was case insensitive would that happen.
Here's one possible:
$(W|w)a(.+)^

Untested, and probably wrong. ;)

I know you called for a regular expression, but if code is an option, here's an easy, verbose way to do it:



$sentence = "My lake is running out of water while I am watering the garden. Walter, did you hear me?";
$keyword = "water";
$values = explode( " ", ereg_replace( "[^[:alnum:]]", " ", $sentence ) );
$substrings = array();
$keylen = strlen( $keyword );

foreach( $values as $word ){
if( !strlen( $word ) )
continue;

$word = strtolower( $word );
$shortest = ( ($l = strlen( $word )) > $keylen ) ? $keylen : $l;

$common = "";

for( $i = 0 ; $i < $shortest ; $i++ ){
if( $word[$i] != $keyword[$i] )
break;

$common .= $word[$i];
}

if( $common )
$substrings[$word] = $common;
}

print_r( $substrings );


Regular expressions will work, but not if the maximal substring isn't known without an expensive use of lookaheads and lookbehinds. Here's a regexp that finds your LCS for you:

"([A-Za-z])\1+"

Just match between your input, and the keyword.


Good luck!
Alex