用这个:

下面的代码将删除'，'。如果你有任何其他字符或子字符串，你可以用它来代替'，'

substr($string, 0, strrpos(substr($string, 0, $comparingLength), ','))

//如果你有另一个字符串帐户

substr($string, 0, strrpos(substr($string, 0, $comparingLength-strlen($currentString)), ','))

/*
Cut the string without breaking any words, UTF-8 aware 
* param string $str The text string to split
* param integer $start The start position, defaults to 0
* param integer $words The number of words to extract, defaults to 15
*/
function wordCutString($str, $start = 0, $words = 15 ) {
    $arr = preg_split("/[\s]+/",  $str, $words+1);
    $arr = array_slice($arr, $start, $words);
    return join(' ', $arr);
}

用法:

$input = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna liqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.';
echo wordCutString($input, 0, 10); 

这将输出前10个单词。

preg_split函数用于将字符串拆分为子字符串。要分割字符串的边界是使用正则表达式模式指定的。

Preg_split函数需要4个参数，但目前只有前3个与我们相关。

第一个参数-模式 第一个参数是要拆分字符串的正则表达式模式。在本例中，我们希望跨单词边界分割字符串。因此，我们使用预定义的字符类\s来匹配空格字符，如空格、制表符、回车和换行。

第二个参数-输入字符串 第二个参数是我们要分割的长文本字符串。

第三个参数-限制 第三个参数指定应该返回的子字符串的数量。如果将限制设置为n，则preg_split将返回一个包含n个元素的数组。前n-1个元素将包含子字符串。最后(第n个)元素将包含字符串的其余部分。

我以前用过这个

<?php
    $your_desired_width = 200;
    $string = $var->content;
    if (strlen($string) > $your_desired_width) {
        $string = wordwrap($string, $your_desired_width);
        $string = substr($string, 0, strpos($string, "\n")) . " More...";
    }
    echo $string;
?>

就我所知，这里所有的解只有在起点固定的情况下才有效。 允许你转动这个: 悲伤之神，神圣之神，痛苦之神，痛苦之神。Ut enim ad minim veniam。 到这个: 神圣的，神圣的… 如果想要截断一组特定关键字周围的单词，该怎么办?

截断一组特定关键字周围的文本。

我们的目标是能够转换这个:

Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna liqua. Ut enim ad minim veniam.

到这个:

...consectetur adipisicing elit, sed do eiusmod tempor...

这是在显示搜索结果、摘要等时非常常见的情况。为了实现这一点，我们可以结合使用以下两种方法:

    /**
     * Return the index of the $haystack matching $needle,
     * or NULL if there is no match.
     *
     * This function is case-insensitive  
     * 
     * @param string $needle
     * @param array $haystack
     * @return false|int
     */
    function regexFindInArray(string $needle, array $haystack): ?int
    {
        for ($i = 0; $i < count($haystack); $i++) {
            if (preg_match('/' . preg_quote($needle) . '/i', $haystack[$i]) === 1) {
                return $i;
            }
        }
        return null;
    }

    /**
     * If the keyword is not present, it returns the maximum number of full 
     * words that the max number of characters provided by $maxLength allow,
     * starting from the left.
     *
     * If the keyword is present, it adds words to both sides of the keyword
     * keeping a balanace between the length of the suffix and the prefix.
     *
     * @param string $text
     * @param string $keyword
     * @param int $maxLength
     * @param string $ellipsis
     * @return string
     */
    function truncateWordSurroundingsByLength(string $text, string $keyword, 
            int $maxLength, string $ellipsis): string
    {
        if (strlen($text) < $maxLength) {
            return $text;
        }

        $pattern = '/' . '^(.*?)\s' .
                   '([^\s]*' . preg_quote($keyword) . '[^\s]*)' .
                   '\s(.*)$' . '/i';
        preg_match($pattern, $text, $matches);

        // break everything into words except the matching keywords, 
        // which can contain spaces
        if (count($matches) == 4) {
            $words = preg_split("/\s+/", $matches[1], -1, PREG_SPLIT_NO_EMPTY);
            $words[] = $matches[2];
            $words = array_merge($words, 
                              preg_split("/\s+/", $matches[3], -1, PREG_SPLIT_NO_EMPTY));
        } else {
            $words = preg_split("/\s+/", $text, -1, PREG_SPLIT_NO_EMPTY);
        }

        // find the index of the matching word
        $firstMatchingWordIndex = regexFindInArray($keyword, $words) ?? 0;

        $length = false;
        $prefixLength = $suffixLength = 0;
        $prefixIndex = $firstMatchingWordIndex - 1;
        $suffixIndex = $firstMatchingWordIndex + 1;

        // Initialize the text with the matching word
        $text = $words[$firstMatchingWordIndex];

        while (($prefixIndex >= 0 or $suffixIndex <= count($words))
                and strlen($text) < $maxLength and strlen($text) !== $length) {
            $length = strlen($text);
            if (isset($words[$prefixIndex])
                and (strlen($text) + strlen($words[$prefixIndex]) <= $maxLength)
                and ($prefixLength <= $suffixLength 
                     or strlen($text) + strlen($words[$suffixIndex]) <= $maxLength)) {
                $prefixLength += strlen($words[$prefixIndex]);
                $text = $words[$prefixIndex] . ' ' . $text;
                $prefixIndex--;
            }
            if (isset($words[$suffixIndex])
                and (strlen($text) + strlen($words[$suffixIndex]) <= $maxLength)
                and ($suffixLength <= $prefixLength 
                     or strlen($text) + strlen($words[$prefixIndex]) <= $maxLength)) {
                $suffixLength += strlen($words[$suffixIndex]);
                $text = $text . ' ' . $words[$suffixIndex];
                $suffixIndex++;
            }
        }

        if ($prefixIndex > 0) {
            $text = $ellipsis . ' ' . $text;
        }
        if ($suffixIndex < count($words)) {
            $text = $text . ' ' . $ellipsis;
        }

        return $text;
    }

现在你可以做:

$text = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do' .
        'iusmod tempor incididunt ut labore et dolore magna liqua. Ut enim' .
        'ad minim veniam.';

$text = truncateWordSurroundingsByLength($text, 'elit', 25, '...');

var_dump($text); // string(32) "... adipisicing elit, sed do ..."

运行代码。

通过使用wordwrap函数。它将文本分割成多行，这样最大宽度就是您指定的宽度，在单词边界处断开。分割之后，你只需取第一行:

substr($string, 0, strpos(wordwrap($string, $your_desired_width), "\n"));

这个线性程序不能处理的一件事是，当文本本身比所需的宽度短时。为了处理这种边情况，我们应该这样做:

if (strlen($string) > $your_desired_width) 
{
    $string = wordwrap($string, $your_desired_width);
    $string = substr($string, 0, strpos($string, "\n"));
}

上面的解决方案存在一个问题，即如果文本在实际切点之前包含换行符，则会过早地切割文本。这里有一个解决这个问题的版本:

function tokenTruncate($string, $your_desired_width) {
  $parts = preg_split('/([\s\n\r]+)/', $string, null, PREG_SPLIT_DELIM_CAPTURE);
  $parts_count = count($parts);

  $length = 0;
  $last_part = 0;
  for (; $last_part < $parts_count; ++$last_part) {
    $length += strlen($parts[$last_part]);
    if ($length > $your_desired_width) { break; }
  }

  return implode(array_slice($parts, 0, $last_part));
}

另外，这里是用于测试实现的PHPUnit测试类:

class TokenTruncateTest extends PHPUnit_Framework_TestCase {
  public function testBasic() {
    $this->assertEquals("1 3 5 7 9 ",
      tokenTruncate("1 3 5 7 9 11 14", 10));
  }

  public function testEmptyString() {
    $this->assertEquals("",
      tokenTruncate("", 10));
  }

  public function testShortString() {
    $this->assertEquals("1 3",
      tokenTruncate("1 3", 10));
  }

  public function testStringTooLong() {
    $this->assertEquals("",
      tokenTruncate("toooooooooooolooooong", 10));
  }

  public function testContainingNewline() {
    $this->assertEquals("1 3\n5 7 9 ",
      tokenTruncate("1 3\n5 7 9 11 14", 10));
  }
}

编辑:

像'à'这样的特殊UTF8字符不会被处理。在REGEX的末尾添加'u'来处理它:

部分美元= preg_split (' / ([\ s \ n \ r] +) / u ',美元字符串,null, PREG_SPLIT_DELIM_CAPTURE);

我是这样做的:

$string = "I appreciate your service & idea to provide the branded toys at a fair rent price. This is really a wonderful to watch the kid not just playing with variety of toys but learning faster compare to the other kids who are not using the BooksandBeyond service. We wish you all the best";

print_r(substr($string, 0, strpos(wordwrap($string, 250), "\n")));