By using the wordwrap function. It splits the texts in multiple lines such that the maximum width is the one you specified, breaking at word boundaries. After splitting, you simply take the first line:

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

One thing this oneliner doesn't handle is the case when the text itself is shorter than the desired width. To handle this edge-case, one should do something like:

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

The above solution has the problem of prematurely cutting the text if it contains a newline before the actual cutpoint. Here a version which solves this problem:

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));
}

Also, here is the PHPUnit testclass used to test the implementation:

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));
  }
}

EDIT :

Special UTF8 characters like 'à' are not handled. Add 'u' at the end of the REGEX to handle it:

$parts = preg_split('/([\s\n\r]+)/u', $string, null, PREG_SPLIT_DELIM_CAPTURE);

This will return the first 200 characters of words:

preg_replace('/\s+?(\S+)?$/', '', substr($string, 0, 201));

$WidgetText = substr($string, 0, strrpos(substr($string, 0, 200), ' '));

And there you have it — a reliable method of truncating any string to the nearest whole word, while staying under the maximum string length.

I've tried the other examples above and they did not produce the desired results.

Keep in mind whenever you're splitting by "word" anywhere that some languages such as Chinese and Japanese do not use a space character to split words. Also, a malicious user could simply enter text without any spaces, or using some Unicode look-alike to the standard space character, in which case any solution you use may end up displaying the entire text anyway. A way around this may be to check the string length after splitting it on spaces as normal, then, if the string is still above an abnormal limit - maybe 225 characters in this case - going ahead and splitting it dumbly at that limit.

One more caveat with things like this when it comes to non-ASCII characters; strings containing them may be interpreted by PHP's standard strlen() as being longer than they really are, because a single character may take two or more bytes instead of just one. If you just use the strlen()/substr() functions to split strings, you may split a string in the middle of a character! When in doubt, mb_strlen()/mb_substr() are a little more foolproof.

Use strpos and substr:

<?php

$longString = "I have a code snippet written in PHP that pulls a block of text.";
$truncated = substr($longString,0,strpos($longString,' ',30));

echo $truncated;

This will give you a string truncated at the first space after 30 characters.

Here you go:

function neat_trim($str, $n, $delim='…') {
   $len = strlen($str);
   if ($len > $n) {
       preg_match('/(.{' . $n . '}.*?)\b/', $str, $matches);
       return rtrim($matches[1]) . $delim;
   }
   else {
       return $str;
   }
}

I would use the preg_match function to do this, as what you want is a pretty simple expression.

$matches = array();
$result = preg_match("/^(.{1,199})[\s]/i", $text, $matches);

The expression means "match any substring starting from the beginning of length 1-200 that ends with a space." The result is in $result, and the match is in $matches. That takes care of your original question, which is specifically ending on any space. If you want to make it end on newlines, change the regular expression to:

$result = preg_match("/^(.{1,199})[\n]/i", $text, $matches);

/*
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);
}

Usage:

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

This will output first 10 words.

The preg_split function is used to split a string into substrings. The boundaries along which the string is to be split, are specified using a regular expressions pattern.

preg_split function takes 4 parameters, but only the first 3 are relevant to us right now.

First Parameter – Pattern The first parameter is the regular expressions pattern along which the string is to be split. In our case, we want to split the string across word boundaries. Therefore we use a predefined character class \s which matches white space characters such as space, tab, carriage return and line feed.

Second Parameter – Input String The second parameter is the long text string which we want to split.

Third Parameter – Limit The third parameter specifies the number of substrings which should be returned. If you set the limit to n, preg_split will return an array of n elements. The first n-1 elements will contain the substrings. The last (n th) element will contain the rest of the string.

You can use this:

function word_shortener($text, $words=10, $sp='...'){

  $all = explode(' ', $text);
  $str = '';
  $count = 1;

  foreach($all as $key){
    $str .= $key . ($count >= $words ? '' : ' ');
    $count++;
    if($count > $words){
      break;
    }
  }

  return $str . (count($all) <= $words ? '' : $sp);

}

Examples:

word_shortener("Hello world, this is a text", 3); // Hello world, this...
word_shortener("Hello world, this is a text", 3, ''); // Hello world, this
word_shortener("Hello world, this is a text", 3, '[read more]'); // Hello world, this[read more]

Edit

How it's work:

1. Explode space from input text:

$all = explode(' ', $text);

for example, if $text will be "Hello world" then $all is an array with exploded values:

["Hello", "world"]

2. For each word:

Select each element in exploded text:

foreach($all as $key){...

Append current word($key) to $str and space if it's the last word:

$str .= $key . ($count >= $words ? '' : ' ');

Then add 1 to $count and check if it's greater than max limit($words) break the loop:

if($count > $words){
   break;
}

Then return $str and separator($sp) only if the final text is less than input text:

return $str . (count($all) <= $words ? '' : $sp);

While this is a rather old question, I figured I would provide an alternative, as it was not mentioned and valid for PHP 4.3+.

You can use the sprintf family of functions to truncate text, by using the %.ℕs precision modifier.

A period . followed by an integer who's meaning depends on the specifier:

• For e, E, f and F specifiers: this is the number of digits to be printed after the decimal point (by default, this is 6).
• For g and G specifiers: this is the maximum number of significant digits to be printed.
• For s specifier: it acts as a cutoff point, setting a maximum character limit to the string

Simple Truncation https://3v4l.org/QJDJU

$string = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
var_dump(sprintf('%.10s', $string));

Result

string(10) "0123456789"

Expanded Truncation https://3v4l.org/FCD21

Since sprintf functions similarly to substr and will partially cut off words. The below approach will ensure words are not cutoff by using strpos(wordwrap(..., '[break]'), '[break]') with a special delimiter. This allows us to retrieve the position and ensure we do not match on standard sentence structures.

Returning a string without partially cutting off words and that does not exceed the specified width, while preserving line-breaks if desired.

function truncate($string, $width, $on = '[break]') {
    if (strlen($string) > $width && false !== ($p = strpos(wordwrap($string, $width, $on), $on))) {
        $string = sprintf('%.'. $p . 's', $string);
    }
    return $string;
}
var_dump(truncate('0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ', 20));

var_dump(truncate("Lorem Ipsum is simply dummy text of the printing and typesetting industry.", 20));

var_dump(truncate("Lorem Ipsum\nis simply dummy text of the printing and typesetting industry.", 20));

Result

/* 
string(36) "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"  
string(14) "Lorem Ipsum is" 
string(14) "Lorem Ipsum
is" 
*/

Results using wordwrap($string, $width) or strtok(wordwrap($string, $width), "\n")

/*
string(14) "Lorem Ipsum is"
string(11) "Lorem Ipsum"
*/

I find this works:

function abbreviate_string_to_whole_word($string, $max_length, $buffer) {
    if (strlen($string) > $max_length) {
        $string_cropped = substr($string, 0, $max_length - $buffer);
        $last_space = strrpos($string_cropped, " ");
        if ($last_space > 0) {
            $string_cropped = substr($string_cropped, 0, $last_space);
        }
        $abbreviated_string = $string_cropped . " ...";
    }
    else {
        $abbreviated_string = $string;
    }
    return $abbreviated_string;
}

The buffer allows you to adjust the length of the returned string.

// a looonnng string ...
$str = "Le Lorem Ipsum est simplement du 
faux texte employé dans la composition et 
la mise en page avant impression. 
Le Lorem Ipsum est le faux texte standard de 
l'imprimerie depuis les années 1500, quand un 
imprimeur anonyme assembla ensemble des morceaux 
de texte pour réaliser un livre spécimen de polices
de texte. Il n'a pas fait que survivre cinq siècles,
mais s'est aussi adapté à la bureautique informatique,
sans que son contenu n'en soit modifié. Il a été 
popularisé dans les années 1960 grâce à la vente 
de feuilles Letraset contenant des passages du
Lorem Ipsum, et, plus récemment, par son inclusion 
dans des applications de mise en page de texte, 
comme Aldus PageMaker";
// number chars to cut
$number_to_cut = 300;
// string truncated in one line !
$truncated_string = 
substr($str, 0, strrpos(substr($str, 0, $number_to_cut), ' '));
// test return
echo $truncated_string;

// variation (add ellipsis) : echo $truncated_string.' ...';

// output :
/* Le Lorem Ipsum est simplement du 
faux texte employé dans la composition et 
la mise en page avant impression. 
Le Lorem Ipsum est le faux texte standard de 
l'imprimerie depuis les années 1500, quand un 
imprimeur anonyme assembla ensemble des morceaux 
de texte pour réaliser un livre
*/

As far as I've seen, all the solutions here are only valid for the case when the starting point is fixed.

Allowing you to turn this:

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

Into this:

Lorem ipsum dolor sit amet, consectetur...

What if you want to truncate words surrounding a specific set of keywords?

Truncate the text surrounding a specific set of keywords.

The goal is to be able to convert this:

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

Into this:

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

Which is a very common situation when displaying search results, excerpts, etc. To achieve this we can use these two methods combined:

    /**
     * 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;
    }

Now you can do:

$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 ..."

Run code.

function trunc($phrase, $max_words) {
       $phrase_array = explode(' ',$phrase);
       if(count($phrase_array) > $max_words && $max_words > 0)
          $phrase = implode(' ',array_slice($phrase_array, 0, $max_words)).'...';
       return $phrase;
    }

Use this:

the following code will remove ','. If you have anyother character or sub-string, you may use that instead of ','

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

// if you have another string account for

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