Question

I have a string variable which contains some text (shown below). The text has line breaks in it as shown. I would like to search the text for a given string, and return the number of matches per line number. For instance, searching for “keyword” would return 1 match on line 3 and 2 matches on line 5.

I have tried using strstr(). It does a good job finding the first match, and giving me the remaining text, so I can do it again and again until there are no matches. Problem is I do not know how to determine which line number the match occurred on.

Hello,
This is some text.
And a keyword.
Some more text.
Another keyword! And another keyword.
Goodby.

Answer 1

Why not split the text on line-feeds and loop, use the index + 1 as a line number:

$txtParts = explode("\n",$txt);
for ($i=0, $length = count($txtParts);$i<$length;$i++)
{
    $tmp = strstr($txtParts[$i],'keyword');
    if ($tmp)
    {
        echo 'Line '.($i +1).': '.$tmp;
    }
}

Tested, and working. Just a quick tip, since you’re looking for matches in a text (sentences, upper- and lower-case etc…) perhaps stristr (case-insensitive) would be better?
An example with foreach and stristr:

$txtParts = explode("\n",$txt);
foreach ($txtParts as $number => $line)
{
    $tmp = stristr($line,'keyword');
    if ($tmp)
    {
        echo 'Line '.($number + 1).': '.$tmp;
    }
}