javascript - 如何定义 JavaScript 中的出现次数？

Question

在 PHP 中，第四个参数将出现次数限制为该数字:

mixed preg_replace ( mixed $pattern , mixed $replacement , mixed $subject [, int $limit = -1 [, int &$count ]] )

例如:

$string = 'this is a test';
$pattern = '/s/';
echo preg_replace($pattern, 'S', $string, 1);
//=> thiS is a test

/* If I remove that 1 which is the last argument in preg_replace, the output will be:
*  "thiS iS a teSt"
*/

我如何在 JavaScript 中执行此操作？

Answer 1

您可以在 replace 方法之外启动一个计数器(就像我在下面的函数中所做的):

function replace($pattern, $replacement, $subject, $limit) {
    var counter = 0;
    return $subject.replace($pattern, function(match) {
        return ++counter > $limit ? match : $replacement;
    });
}

var $string = 'this is a test';
var $pattern = /s/g;

O.innerHTML = replace($pattern, 'S', $string, 1) + '\n'
              + replace($pattern, 'S', $string, 2);

<pre id=O>

希望对您有所帮助:)