从字符串中获取前100个字符，并注意完整单词

我之前在这里问过类似的问题，但是我需要知道这种小的调整是否可能。我想将一个字符串缩短为100个字符，并使用它$small = substr($big, 0, 100);来做到这一点。但是，这只需要前100个字符，并不在乎是否分解一个单词。

有什么方法可以占用一个字符串的前100个字符，但要确保您不会打断一个单词？

例：

$big = "This is a sentence that has more than 100 characters in it, and I want to return a string of only full words that is no more than 100 characters!"

$small = some_function($big);

echo $small;

// OUTPUT: "This is a sentence that has more than 100 characters in it, and I want to return a string of only"

Is there a way to do this using PHP?

All you need to do is use:

$pos=strpos($content, ' ', 200);
substr($content,0,$pos ); 

Yes, there is. This is a function I borrowed from a user on a different forums a a few years back, so I can't take credit for it.

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

Note that it automatically adds ellipses, if you don't want that just use '\\1' as the second parameter for the preg_replace call.

If you define words as "sequences of characters delimited by space"... Use strrpos() to find the last space in the string, shorten to that position, trim the result.

This is my approach, based on amir's answer, but it doesn't let any word make the string longer than the limit, by using strrpos() with a negative offset.

Simple but works. I'm using the same syntax as in Laravel's str_limit() helper function, in case you want to use it on a non-Laravel project.

function str_limit($value, $limit = 100, $end = '...')
{
    $limit = $limit - mb_strlen($end); // Take into account $end string into the limit
    $valuelen = mb_strlen($value);
    return $limit < $valuelen ? mb_substr($value, 0, mb_strrpos($value, ' ', $limit - $valuelen)) . $end : $value;
}

Sure. The easiest is probably to write a wrapper around preg_match:

function limitString($string, $limit = 100) {
    // Return early if the string is already shorter than the limit
    if(strlen($string) < $limit) {return $string;}

    $regex = "/(.{1,$limit})\b/";
    preg_match($regex, $string, $matches);
    return $matches[1];
}

EDIT : Updated to not ALWAYS include a space as the last character in the string

This function shortens a string by adding "..." at a word boundary whenever possible. The returned string will have a maximum length of $len including "...".

function truncate($str, $len) {
  $tail = max(0, $len-10);
  $trunk = substr($str, 0, $tail);
  $trunk .= strrev(preg_replace('~^..+?[\s,:]\b|^...~', '...', strrev(substr($str, $tail, $len-$tail))));
  return $trunk;
}

Examples outputs:

• truncate("Thanks for contributing an answer to Stack Overflow!", 15)
  returns "Thanks for..."
• truncate("To learn more, see our tips on writing great answers.", 15)
  returns "To learn more..." (comma also truncated)
• truncate("Pseudopseudohypoparathyroidism", 15)
  returns "Pseudopseudo..."

This works fine for me, I use it in my script

<?PHP
$big = "This is a sentence that has more than 100 characters in it, and I want to return a string of only full words that is no more than 100 characters!";
$small = some_function($big);
echo $small;

function some_function($string){
     $string = substr($string,0,100);
     $string = substr($string,0,strrpos($string," "));
     return $string;
}
?>

good luck

Here is great solution with dotts at the end with full words

function text_cut($text, $length = 200, $dots = true) {
    $text = trim(preg_replace('#[\s\n\r\t]{2,}#', ' ', $text));
    $text_temp = $text;
    while (substr($text, $length, 1) != " ") { $length++; if ($length > strlen($text)) { break; } }
    $text = substr($text, 0, $length);
    return $text . ( ( $dots == true && $text != '' && strlen($text_temp) > $length ) ? '...' : ''); 
}

Input: Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Output: Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip...

The problem with accepted answer is that result string goes over the the limit, i.e. it can exceed 100 chars since strpos will look after the offset and so your length will always be a over your limit. If the last word is long, like squirreled then the length of your result will be 111 (to give you an idea).

A better solution is to use wordwrap function:

function truncate($str, $length = 125, $append = '...') {
    if (strlen($str) > $length) {
        $delim = "~\n~";
        $str = substr($str, 0, strpos(wordwrap($str, $length, $delim), $delim)) . $append;
    } 

    return $str;
}


echo truncate("The quick brown fox jumped over the lazy dog.", 5);

This way you can be sure the string is truncated under your limit (and never goes over)

P.S. This is particularly useful if you plan to store the truncated string in your database with a fixed-with column like VARCHAR(50), etc.

P.P.S. Note the special delimiter in wordwrap. This is to make sure that your string is truncated correctly even when it contains newlines (otherwise it will truncate at first newline which you don't want).

This did it for me...

//trim message to 100 characters, regardless of where it cuts off
$msgTrimmed = mb_substr($var,0,100);

//find the index of the last space in the trimmed message
$lastSpace = strrpos($msgTrimmed, ' ', 0);

//now trim the message at the last space so we don't cut it off in the middle of a word
echo mb_substr($msgTrimmed,0,$lastSpace)

Here's my solution:

/**
 * get_words_until() Returns a string of delimited text parts up to a certain length
 * If the "words" are too long to limit, it just slices em up to the limit with an ellipsis "..."
 *
 * @param $paragraph - The text you want to Parse
 * @param $limit - The maximum character length, e.g. 160 chars for SMS
 * @param string $delimiter - Use ' ' for words and '. ' for sentences (abbreviation bug) :)
 * @param null $ellipsis - Use '...' or ' (more)' - Still respects character limit
 *
 * @return string
 */
function get_words_until($paragraph, $limit, $delimiter = ' ', $ellipsis = null)
{
    $parts = explode($delimiter, $paragraph);

    $preview = "";

    if ($ellipsis) {
        $limit = $limit - strlen($ellipsis);
    }

    foreach ($parts as $part) {
        $to_add = $part . $delimiter;
        if (strlen($preview . trim($to_add)) <= $limit) { // Can the part fit?
            $preview .= $to_add;
            continue;
        }
        if (!strlen($preview)) { // Is preview blank?
            $preview = substr($part, 0, $limit - 3) . '...'; // Forced ellipsis
            break;
        }
    }

    return trim($preview) . $ellipsis;
}

In your case it would be (example):

$big = "This is a sentence that has more than 100 characters in it, and I want to return a string of only full words that is no more than 100 characters!"

$small = get_words_until($big, 100);

function truncate ($str, $length) {
    if (strlen($str) > $length) {
        $str = substr($str, 0, $length+1);
        $pos = strrpos($str, ' ');
        $str = substr($str, 0, ($pos > 0)? $pos : $length);
    }
    return $str;
}

Example:

print truncate('The first step to eternal life is you have to die.', 25);

string(25) "The first step to eternal"

print truncate('The first step to eternal life is you have to die.', 12);

string(9) "The first"

print truncate('FirstStepToEternalLife', 5);

string(5) "First"

I apologize for resurrecting this question but I stumbled upon this thread and found a small issue. For anyone wanting a character limit that will remove words that would go above your given limit, the above answers work great. In my specific case, I like to display a word if the limit falls in the middle of said word. I decided to share my solution in case anyone else is looking for this functionality and needs to include words instead of trimming them out.

function str_limit($str, $len = 100, $end = '...')
{
    if(strlen($str) < $len)
    {
        return $str;
    }

    $str = preg_replace("/\s+/", ' ', str_replace(array("\r\n", "\r", "\n"), ' ', $str));

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

    $out = '';
    foreach(explode(' ', trim($str)) as $val)
    {
        $out .= $val . ' ';

        if(strlen($out) >= $len)
        {
            $out = trim($out);
            return (strlen($out) == strlen($str)) ? $out : $out . $end;
        }
    }
}

Examples:

• Input: echo str_limit('Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.', 100, '...');
• Output: Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore...
• Input: echo str_limit('Lorem ipsum', 100, '...');
• Output: Lorem ipsum
• Input: echo str_limit('Lorem ipsum', 1, '...');
• Output: Lorem...

Here is another way you can do that.

$big = "This is a sentence that has more than 100 characters in it, and I want to return a string of only full words that is no more than 100 characters!"
$big = trim( $big );
$small = $big;
                if( strlen( $big ) > 100 ){
                $small = mb_substr( $small, 0, 100 );
                $last_position = mb_strripos( $small, ' ' );
                    if( $last_position > 0 ){
                    $small = mb_substr( $small, 0, $last_position );
                    }
                }

            echo $small; 

OR

 echo ( strlen( $small ) <  strlen( $big ) ? $small.'...' : $small );

This is also multibyte safe and also works even if there are not spaces, in which case it will just simply return first 100 characters. It takes the first 100 characters and then searches from the end till the nearest word delimiter.

Yet another answer! I wasn't completely satisfied with other answers, and wanted a 'hard cutoff' (guaranteed word break before $max_characters, if possible), so here's my function to contribute!

/**
 * Shortens a string (if necessary), trying for a non-word character before character limit, adds an ellipsis and
 * returns. Falls back to a forced cut if no non-word characters exist before.
 *
 * @param string $content
 * @param int    $max_characters - number of characters to start looking for a space / break.
 * @param bool   $add_ellipsis   - add ellipsis if content is shortened
 *
 * @return string
 */
public static function shorten( $content, $max_characters = 100, $add_ellipsis = TRUE ) {
    if ( strlen( $content ) <= $max_characters ) {
        return $content;
    }

    // search for non-word characters
    $match_count = preg_match_all( '/\W/', $content, $matches, PREG_OFFSET_CAPTURE );

    // force a hard break if can't find another good solution
    $pos = $max_characters;

    if ( $match_count > 0 ) {
        foreach ( $matches[0] as $match ) {
            // check if new position fits within
            if ( $match[1] <= $max_characters ) {
                $pos = $match[1];
            } else {
                break;
            }
        }
    }

    $suffix = ( $add_ellipsis ) ? '&hellip;' : '';

    return substr( $content, 0, $pos ) . $suffix;
}

Another a simpler way I do.

function limit_words($string, $word_limit = 10)
{
    $words = explode(" ", $string);
    if (count($words) > $word_limit) {
        return implode(" ", array_splice($words, 0, $word_limit)) . ' ...';
    }
    return implode(" ", array_splice($words, 0, $word_limit));
}

wordwrap formats string according to limit, seprates them with \n so we have lines smaller than 50, ords are not seprated explodes seprates string according to \n so we have array corresponding to lines list gathers first element.

list($short) = explode("\n",wordwrap($ali ,50));

please rep Evert, since I cant comment or rep.

here is sample run

php >  $ali = "ali veli krbin yz doksan esikesiksld sjkas laksjald lksjd asldkjadlkajsdlakjlksjdlkaj aslkdj alkdjs akdljsalkdj ";
php > list($short) = explode("\n",wordwrap($ali ,50));
php > var_dump($short);
string(42) "ali veli krbin yz doksan esikesiksld sjkas"
php > $ali ='';
php > list($short) = explode("\n",wordwrap($ali ,50));
php > var_dump($short);
string(0) ""

## Get first limited character from a string ##

<?php 
  $content= $row->title;
  $result = substr($content, 0, 70);
  echo $result; 
  ?>