限制字符串长度

You can use the wordwrap() function then explode on newline and take the first part, if you don't want to split words.

$str = 'Stack Overflow is as frictionless and painless to use as we could make it.';
$str = wordwrap($str, 28);
$str = explode("\n", $str);
$str = $str[0] . '...';

Source: https://stackoverflow.com/a/1104329/1060423

If you don't care about splitting words, then simply use the php substr function.

echo substr($str, 0, 28) . '...';

Do a little homework with the php online manual's string functions. You'll want to use strlen in a comparison setting, substr to cut it if you need to, and the concatenation operator with "..." or "…"

You can use something similar to the below:

if (strlen($str) > 10)
$str = substr($str, 0, 7) . '...';

To truncate a string provided by the maximum limit without breaking a word use this:

/**
* truncate a string provided by the maximum limit without breaking a word
* @param string $str
* @param integer $maxlen
* @return string
*/
public static function truncateStringWords($str, $maxlen): string
{
if (strlen($str) <= $maxlen) return $str;


$newstr = substr($str, 0, $maxlen);
if (substr($newstr, -1, 1) != ' ') $newstr = substr($newstr, 0, strrpos($newstr, " "));


return $newstr;
}

From php 4.0.6 , there is a function for the exact same thing

function mb_strimwidth can be used for your requirement

<?php
echo mb_strimwidth("Hello World", 0, 10, "...");
//Hello W...
?>

It does have more options though,here is the documentation for this mb_strimwidth

In another way to limit a string in php and add on readmore text or like '...' using below code

if (strlen(preg_replace('#^https?://#', '', $string)) > 30) {
echo substr(preg_replace('#^https?://#', '', $string), 0, 35).'…';
}

In Laravel, there is a string util function for this, and it is implemented this way:

public static function limit($value, $limit = 100, $end = '...')
{
if (mb_strwidth($value, 'UTF-8') <= $limit) {
return $value;
}


return rtrim(mb_strimwidth($value, 0, $limit, '', 'UTF-8')).$end;
}

$value = str_limit('This string is really really long.', 7);

// This st...

2nd argument is where to start string and 3rd argument how many characters you need to show

$title = "This is for testing string for get limit of string This is for testing string for get limit of string This is for testing string for get limit of string This is for testing string for get limit of string";
echo substr($title,0,50);

$res = explode("\n",wordwrap('12345678910', 8, "...\n",true))[0];


// $res will be  : "12345678..."

function truncateString($string, $maxlength, $ellipsis = false){


if(mb_strlen($string) <= $maxlength){
return $string;
}


if(empty($ellipsis)){
$ellipsis = '';
}


if($ellipsis === true){
$ellipsis = '…';
}


$ellipsis_length = mb_strlen($ellipsis);


$maxlength = $maxlength - $ellipsis_length;


$string = trim(mb_substr($string, 0, $maxlength)) . $ellipsis;


return $string;


}

http://sandbox.onlinephpfunctions.com/code/968e2fd1e98b60828a12d6dc0b68ec38b3628757

 $string = (strlen($string) > 13) ? substr($string,0,10).'...' : $string;

Or as function:

function truncate($string, $length, $dots = "...") {
return (strlen($string) > $length) ? substr($string, 0, $length - strlen($dots)) . $dots : $string;
}

It's been a while since I wrote this answer and I don't actually use this code any more. I prefer this function which prevents breaking the string in the middle of a word using the wordwrap function:

function truncate($string,$length=100,$append="…") {
$string = trim($string);


if(strlen($string) > $length) {
$string = wordwrap($string, $length);
$string = explode("\n", $string, 2);
$string = $string[0] . $append;
}


return $string;
}

function showAHumanDate( $dateString ){
$toRet = '';
$days = date( "d", strtotime( $dateString ) );
$month = date( "F", strtotime( $dateString ) );
$year = date( "Y", strtotime( $dateString ) );


switch( $days ){
case '01':
$string = '1st';
break;
case '02':
$string = '2nd';
break;
case '03':
$string = '3rd';
break;
case '21':
$string = '21st';
break;
case '22':
$string = '22nd';
break;
case '23':
$string = '23rd';
break;
case '31':
$string = '31st';
break;
default:
$string = $days.'th';
}


// strip the month to three letters:
$month = mb_strimwidth( $month, 0, 3, '' );


$toRet = $string.' '.$month.' '.$year;
return $toRet;


}