How to shorten a string without slicing through a word while keeping within a character limit in PHP

Question

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How to Truncate a string in PHP to the word closest to a certain number of characters?

How can I shorten a string to a maximum of 140 chars without slicing through a word.

Take the following string:

$string = "This is an example string that contains more than 140 characters. If I use PHPs substring function it will split it in the middle of this word."

Using substr($string, 0, 140) we would get something like this:

This is an example string that contains more than 140 characters. If I use PHPs substring function it will split it in the middle of this wo

Notice it sliced through the word "word".

What I need is to be able to shorten a string while preserving entire words but without going over 140 characters.

I did find the following code but even though it will preserve entire words, it does not guarantee that the entire string does not go over the 140 char limit:

function truncate($text, $length) {
   $length = abs((int)$length);
   if(strlen($text) > $length) {
      $text = preg_replace("/^(.{1,$length})(\s.*|$)/s", '\\1...', $text);
   }
   return($text);
}

Answer 1

If the string is too long, you can first use substr to truncate the string and then a regular expression to remove the last full or partial word:

$s = substr($s, 0, (140 - 3));
$s = preg_replace('/ [^ ]*$/', ' ...', $s);

Note that you have to make the original shorter than 140 bytes because when you add the ... this could increase the length of the string beyond 140 bytes.

Answer 2

I don't know php very well but here is how you can do it with approximative syntax

$total_length = 0;

$words = $whole_sentense->split(' ')

$word_index = 0

$final_sentense = ''

while($total_length + strlen($words[$word_index]) < 140)
{
  $final_sentense .= words[$word_index]
  $total_length += strlen($words[$word_index]
  $word_index++
}

return ($final_sentense)

Answer 3

You could use strrpos to find the last space character in the string:

function truncate($text, $length = 140) {
    if(strlen($text) > $length) {
        // $length - strlen($text) is used to find the last occurrence of a blank
        // UP TO the $length character in the string.
        $text = substr($text, 0, strrpos($text,' ', $length - strlen($text) ));
    }
    return $text;
}

It wouldn't add ... though. For this to work you can change the function to:

function truncate($text, $length = 140) {
    if(strlen($text) > $length) {
        $text = substr($text, 0, strrpos($text,' ', $length - strlen($text)-3)) . '...';
    }
    return $text;
}

Answer 4

You may want to look at strtok in the php manual.

What you can do is run a loop and add the token's strlen every time until you exceed your desired length.

Answer 5

Found the solution in a previous question as pointed out by @Jordan: http://stackoverflow.com/questions/79960/how-to-truncate-a-string-in-php-to-the-word-closest-to-a-certain-number-of-charac/79986#79986

Answer 6

//beak into 140 character chunks
$strParts = str_split( $str, 140 );

//if the first character of the second chunk is not whitespace
if( isset( $strParts[1] ) && !preg_match( '/^\s/', $strParts[1] ) {
    //strip off the last partial word from the first chunk
    $strParts[0] = preg_replace( '/\s\w+$/', '', $strParts[0] );
}

//you're done
$str = $strParts[0];

Answer 7

This is the function Drupal uses to shorten strings without breaking up words.

//$wordsafe: set to TRUE to not truncate in middle of words
//$dots: set to TRUE to add " ..." to the end of the truncated string
function truncate_utf8($string, $len, $wordsafe = FALSE, $dots = FALSE) {

  if (strlen($string) <= $len) {
    return $string;
  }

  if ($dots) {
    $len -= 4;
  }

  if ($wordsafe) {
    $string = substr($string, 0, $len + 1); // leave one more character
    if ($last_space = strrpos($string, ' ')) { // space exists AND is not on position 0
      $string = substr($string, 0, $last_space);
    }
    else {
      $string = substr($string, 0, $len);
    }
  }
  else {
    $string = substr($string, 0, $len);
  }

  if ($dots) {
    $string .= ' ...';
  }

  return $string;
}

Answer 8

How about using a regular expression to find all of the whitespace, then truncate at the the match that is largest but still less than or equal to your desired length.

function truncate($text, $length) {
    $length = abs((int)$length);

    $count = preg_match_all("(\s+)", $text, $matches, PREG_OFFSET_CAPTURE);

    while ($count > 0) {
       if ($matches[$count][0] <= $length) {
          $length = $matches[$count][0];
          break;
       }    
       $count = $count - 1;
    }

    return substr($text, 0, $length)
}

Answer 9

Also strings are unlikely to have tabs, \t, in them so you can do this

$str = word_wrap( $str, 140, "\t" );
$str = explode( "\t", $str );
$str = $str[0];