Ver: 0.7.1
You are at: http://STauren.net/log/e79g7ao3a.html
- Title: trim的13种写法（孔乙己？）
- 0/47
- stauren
IP hidden - 2008-02-22 17:01
81 days ago
javascript没有提供直接的字符串trim方法，所以开发者们进行了各种实现，就像下面这些：
他们的性能如下：
想自己试验一下的可以到这里
另外作者还提到了一种在lib里面存在的错误的方法
呵呵，你知道吗，trim可以有12种写法
1. return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
2. return str.replace(/^\s+/, '').replace(/\s+$/, '');
3. return str.substring(Math.max(str.search(/\S/), 0), str.search(/\S\s*$/) + 1);
4. return str.replace(/^\s+|\s+$/g, '');
5. str = str.match(/\S+(?:\s+\S+)*/); return str ? str[0] : '';
6. return str.replace(/^\s*(\S*(\s+\S+)*)\s*$/, '$1');
7. return str.replace(/^\s*(\S*(?:\s+\S+)*)\s*$/, '$1');
8. return str.replace(/^\s*((?:[\S\s]*\S)?)\s*$/, '$1');
9. return str.replace(/^\s*([\S\s]*?)\s*$/, '$1');
10. function trim10 (str) {
var whitespace = ' \n\r\t\f\x0b\xa0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000';
for (var i = 0; i < str.length; i++) {
if (whitespace.indexOf(str.charAt(i)) === -1) {
str = str.substring(i);
break;
}
}
for (i = str.length - 1; i >= 0; i--) {
if (whitespace.indexOf(str.charAt(i)) === -1) {
str = str.substring(0, i + 1);
break;
}
}
return whitespace.indexOf(str.charAt(0)) === -1 ? str : '';
}
11. function trim11 (str) {
str = str.replace(/^\s+/, '');
for (var i = str.length - 1; i >= 0; i--) {
if (/\S/.test(str.charAt(i))) {
str = str.substring(0, i + 1);
break;
}
}
return str;
}他们的性能如下：
| Method | Firefox 2 | IE 6 |
|---|---|---|
| trim1 | 15ms | < 0.5ms |
| trim2 | 31ms | < 0.5ms |
| trim3 | 46ms | 31ms |
| trim4 | 47ms | 46ms |
| trim5 | 156ms | 1656ms |
| trim6 | 172ms | 2406ms |
| trim7 | 172ms | 1640ms |
| trim8 | 281ms | < 0.5ms |
| trim9 | 125ms | 78ms |
| trim10 | < 0.5ms | < 0.5ms |
| trim11 | < 0.5ms | < 0.5ms |
想自己试验一下的可以到这里
另外作者还提到了一种在lib里面存在的错误的方法
！错误！ return str.replace(/^\s*([\S\s]*)\b\s*$/, '$1');最后，在各个浏览器长字符串表现都很好的trim11，作者还提供了最终的优化版trim12 function trim12 (str) {
var str = str.replace(/^\s\s*/, ''),
ws = /\s/,
i = str.length;
while (ws.test(str.charAt(--i)));
return str.slice(0, i + 1);
}呵呵，你知道吗，trim可以有12种写法
Birthday
1984-05-29:(15 days away)
李旭
1983-06-21:(38 days away)
肖琦
1984-06-29:(46 days away)
周旭
1983-07-07:(54 days away)
于洋
李旭
1983-06-21:(38 days away)
肖琦
1984-06-29:(46 days away)
周旭
1983-07-07:(54 days away)
于洋
Please login
Time
Calendar
Friend links
Announcement
stauren@西湖湖畔
JavaScript is the world's most misunderstood programming language. The language has so much expressive power that it is possible to be somewhat productive with it without knowing what you're doing. But that is not an effective way to work. Programming is serious business that should never be undertaken in ignorance.
Listen Yahoo!
Let's start from here!
一般的SB都是酷酷的
Belle
JavaScript is the world's most misunderstood programming language. The language has so much expressive power that it is possible to be somewhat productive with it without knowing what you're doing. But that is not an effective way to work. Programming is serious business that should never be undertaken in ignorance.
Listen Yahoo!
Let's start from here!
一般的SB都是酷酷的
Belle
My Project
stauren.net is proudly powered by STauren! blog, a small ajax blog framework developed by stauren.
All we got here, are memories. With heart & soul. 2006-2008 STauren! © Ver 0.7.1
All we got here, are memories. With heart & soul. 2006-2008 STauren! © Ver 0.7.1