如何在PHP中将字符串截断为前20个单词？

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);

输出：

Hello here is a long ...

将数字更改为下面的数字以获取前 20 个单词，或将其作为参数传递。下面演示如何获取前 3 个单词：（因此将 to 更改为更改默认值）：320320

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(""));  # => ""