extract part of a string before and after a word - php

Question

i need to extract and show some words before and after a query word, something like google search results, for example:
$str = "hi user! welcome to new php open source world, we are trying to learn you something!";
$query = "new php";
$result = "... welcome to new php open source ...";
i searched google an SO but didn't find a clear answer or maybe my php knowledge was not enough!
is there a workable and easy-to-use function to do this job?

Answer 1

function yourFuncName($str, $query, $numOfWordToAdd) {
list($before, $after) = explode($query, $str);
$before = rtrim($before);
$after = ltrim($after);
$beforeArray = array_reverse(explode(" ", $before));
$afterArray = explode(" ", $after);
$countBeforeArray = count($beforeArray);
$countAfterArray = count($afterArray);
$beforeString = "";
if($countBeforeArray < $numOfWordToAdd) {
$beforeString = implode(' ', $beforeArray);
}
else {
for($i = 0; $i < $numOfWordToAdd; $i++) {
$beforeString = $beforeArray[$i] . ' ' . $beforeString;
}
}
$afterString = "";
if($countAfterArray < $numOfWordToAdd) {
$afterString = implode(' ', $afterArray);
}
else {
for($i = 0; $i < $numOfWordToAdd; $i++) {
$afterString = $afterString . $afterArray[$i] . ' ';
}
}
$string = $beforeString . $query . ' ' . $afterString;
return $string;
}
Output is: user! welcome to new php open source world, ($numOfWordToAdd = 3)

Answer 2

Here is an working example I thing that it is clear what I did and how:
<?php
$str = "hi user! welcome to new php open source world, we are trying to learn you something!";
$query = "new php";
$expl = explode($query, $str);
// items on the left side of middle string
$expl_left = explode(" ", $expl[0]);
$left_cnt = count($expl_left);
$new_left = $expl_left[$left_cnt-3] . " " . $expl_left[$left_cnt-2];
// items on the right side of middle string
$expl_right = explode(" ", $expl[1]);
$new_right = $expl_right[1] . " " . $expl_right[2];
// new string formated
$new = "... " . $new_left . " " . $query . " " . $new_right . " ...";
print $new;
?>
If you have some questions feel free to ask...

Answer 3

$result = preg_replace('/(.+)?([^\s]+.{10}'.$query.'.{10}[^\s]+)(.+)?/', '... $2 ...', $str);
This will return the same result from the same string and query you gave. If the before or after length starts or ends (respectively) in the middle of a word, it will continue until it completes the word before it stops.

Answer 4

Assuming a "word" is any series of non-whitespace characters, the following will extract 3 words on either side of new php out of the string $subject, but accept less if necessary:
if (preg_match('/(?:\S+\s+){1,3}new php(?:\s+\S+){1,3}/', $subject, $regs)) {
$result = $regs[0];
}
Change the 3s to any number you like.

Answer 5

I used the following function with explode:
public static function returnSearch($query, $str, $wordcount) {
$explode = explode($query, $str);
$result = null;
//if explode count is one the query was not found
if (count($explode) == 1) {
$result = implode(' ', array_slice(str_word_count($explode[0], 2), -$wordcount, $wordcount)) . " ";
}
//if explode count is more than one the query was found at least one time
if (count($explode) > 1) {
//check for if the string begins with the query
if (!empty($explode[0])) {
$result = "..." . implode(' ', array_slice(str_word_count($explode[0], 2), -$wordcount, $wordcount)) . " ";
}
$result = $result . $query;
if (!empty($explode[1])) {
$result = $result . " " . implode(' ', array_slice(str_word_count($explode[1], 2), 0, $wordcount)) . "...";
}
}
//return result
return $result;
}

Answer 6

Corrected function from #Can Vural, it wont mess the phrase of the before match and its case insensitive, very usefull to dispaly in php search results:
function render_search_words($str, $query, $numOfWordToAdd) {
list($before, $after) = preg_split("/$query/i", $str);
$before = rtrim($before);
$after = ltrim($after);
$beforeArray = explode(" ", $before);
$afterArray = explode(" ", $after);
$countBeforeArray = count($beforeArray);
$countAfterArray = count($afterArray);
$beforeString = "";
if($countBeforeArray < $numOfWordToAdd) {
$beforeString = implode(' ', $beforeArray);
}
else {
for($i = 0; $i < $numOfWordToAdd; $i++) {
$beforeString = $beforeArray[$i] . ' ' . $beforeString;
}
}
$afterString = "";
if($countAfterArray < $numOfWordToAdd) {
$afterString = implode(' ', $afterArray);
}
else {
for($i = 0; $i < $numOfWordToAdd; $i++) {
$afterString = $afterString . $afterArray[$i] . ' ';
}
}
$string = '...'.$beforeString . ' <span>' . $query . '</span> ' . $afterString.'...';
return $string;
}