问php:通过子子串从字符串中提取子串

EN

$txt = "word word word different. different word word word. word word word ending. word word word";

$word = "different";

$c=preg_match("/(\.|^)([^\.]*?".$word."[^\.]*(\.|$))/",$txt,$match);

if($c!==false and count($match) > 0 )
    echo( $match[2]) ;

<?php

$text="Here are some text. The word is inside of the second sentence. And the word is also in this sentence!";
$word = 'word';


function getSentenceByWord($text, $word) {

    $sentences = preg_split('/(\.|\?|\!)(\s)/',$text);
    $matches = array();
    foreach($sentences as $sentence) {

        if (strpos($sentence,$word) !== false) {
            $matches[] = $sentence;
        }

    }

    return $matches;
}

print_r(getSentenceByWord($text, $word));
?>

Array
(
    [0] => The word is inside of the second sentence
    [1] => And the word is also in this sentence!
)

<?php
$text="Sentence one. Sentence two. Sentence three. Sentence four.";

$word_pos = strpos($text, "Sentence");
$start = strrpos(substr($text, 0, $word_pos), ".");
$end = strpos(substr($text, $word_pos), ".");

$start = $start ? $start + 2 : 0;
$end = $end + $word_pos + 1 - $start;

$sentence = substr($text, $start, $end);

echo $sentence;