PHP preg_split:由其他字符串拆分字符串

Question

我想通过一系列单词拆分一个大字符串.

例如

$splitby = array('these','are','the','words','to','split','by');
$text = 'This is the string which needs to be split by the above words.';

然后结果将是:

$text[0]='This is';
$text[1]='string which needs';
$text[2]='be';
$text[3]='above';
$text[4]='.';

我怎样才能做到这一点？是preg_split最好的方法,还是有更有效的方法？我希望它尽可能快,因为我将分割数百MB的文件.

Answer 1

这应该是合理有效的.但是,您可能希望使用某些文件进行测试并报告性能.

$splitby = array('these','are','the','words','to','split','by');
$text = 'This is the string which needs to be split by the above words.';
$pattern = '/\s?'.implode($splitby, '\s?|\s?').'\s?/';
$result = preg_split($pattern, $text, -1, PREG_SPLIT_NO_EMPTY);

• 正则表达式演示:http://rubular.com/r/jNUO1KvrXg
• PHP代码演示:http://www.ideone.com/ov3Wl

Answer 2

preg_split可以用作：

$pieces = preg_split('/'.implode('\s*|\s*',$splitby).'/',$text,-1,PREG_SPLIT_NO_EMPTY);

看见

Answer 3

我不认为使用 pcre 正则表达式是必要的......如果它确实是您需要的单词分割。

你可以做这样的事情并进行基准测试，看看它是否更快/更好......

$splitby = array('these','are','the','words','to','split','by');
$text = 'This is the string which needs to be split by the above words.';

$split = explode(' ', $text);
$result = array();
$temp = array();

foreach ($split as $s) {

    if (in_array($s, $splitby)) {
        if (sizeof($temp) > 0) {
           $result[] = implode(' ', $temp);
           $temp = array();
        }            
    } else {
        $temp[] = $s;
    }
}

if (sizeof($temp) > 0) {
    $result[] = implode(' ', $temp);
}

var_dump($result);

/* output

array(4) {
  [0]=>
  string(7) "This is"
  [1]=>
  string(18) "string which needs"
  [2]=>
  string(2) "be"
  [3]=>
  string(5) "above words."
}

与您的输出的唯一区别是最后一个单词，因为“单词”。!= "word" 并且它不是一个分割词。