How can I truncate a string to the first 20 words in PHP?

To Nearest Space

Truncates to nearest preceding space of target character. Demo

• $str The string to be truncated
• $chars The amount of characters to be stripped, can be overridden by $to_space
• $to_space boolean for whether or not to truncate from space near $chars limit

Function

function truncateString($str, $chars, $to_space, $replacement="...") {
   if($chars > strlen($str)) return $str;

   $str = substr($str, 0, $chars);
   $space_pos = strrpos($str, " ");
   if($to_space && $space_pos >= 0) 
       $str = substr($str, 0, strrpos($str, " "));

   return($str . $replacement);
}

Sample

<?php

$str = "this is a string that is just some text for you to test with";

print(truncateString($str, 20, false) . "\n");
print(truncateString($str, 22, false) . "\n");
print(truncateString($str, 24, true) . "\n");
print(truncateString($str, 26, true, " :)") . "\n");
print(truncateString($str, 28, true, "--") . "\n");

?>

Output

this is a string tha...
this is a string that ...
this is a string that...
this is a string that is :)
this is a string that is--

function limit_text($text, $limit) {
    if (str_word_count($text, 0) > $limit) {
        $words = str_word_count($text, 2);
        $pos   = array_keys($words);
        $text  = substr($text, 0, $pos[$limit]) . '...';
    }
    return $text;
}

echo limit_text('Hello here is a long sentence that will be truncated by the', 5);

Outputs:

Hello here is a long ...

Change the number 3 to the number 20 below to get the first 20 words, or pass it as parameter. The following demonstrates how to get the first 3 words: (so change the 3 to 20 to change the default value):

function first3words($s, $limit=3) {
    return preg_replace('/((\w+\W*){'.($limit-1).'}(\w+))(.*)/', '${1}', $s);   
}

var_dump(first3words("hello yes, world wah ha ha"));  # => "hello yes, world"
var_dump(first3words("hello yes,world wah ha ha"));   # => "hello yes,world"
var_dump(first3words("hello yes world wah ha ha"));   # => "hello yes world"
var_dump(first3words("hello yes world"));  # => "hello yes world"
var_dump(first3words("hello yes world.")); # => "hello yes world"
var_dump(first3words("hello yes"));  # => "hello yes"
var_dump(first3words("hello"));  # => "hello"
var_dump(first3words("a")); # => "a"
var_dump(first3words(""));  # => ""