JavaScript indexOf() - 如何获取特定索引
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JavaScript indexOf() - how to get specific index
提问by Itai Sagi
Let's say I have a URL:
假设我有一个 URL：
http://something.com/somethingheretoo
and I want to get what's after the 3rd instance of /?
我想知道第三个实例之后是/什么？
something like the equivalent of indexOf()which lets me input which instance of the backslash I want.
类似于indexOf()which 让我输入我想要的反斜杠实例的东西。
采纳答案by Kelly
If you know it starts with http://or https://, just skip past that part with this one-liner:
如果您知道它以http://或开头https://，只需使用此单行跳过该部分：
var content = aURL.substring(aURL.indexOf('/', 8));
This gives you more flexibility if there are multiple slashes in that segment you want.
如果您想要的该段中有多个斜杠，这将为您提供更大的灵活性。
回答by PiTheNumber
s = 'http://something.com/somethingheretoo';
parts = s.split('/');
parts = parts.slice(0, 2);
return parts.join('/');
回答by bjornruysen
Another approach is to use the Javascript "split" function:
另一种方法是使用 Javascript "split" 函数：
var strWord = "me/you/something";
var splittedWord = strWord.split("/");
splittedWord[0] would return "me"
splittedWord[0] 将返回“我”
splittedWord[1] would return "you"
splittedWord[1] 将返回“你”
splittedWord[2] would return "something"
splittedWord[2] 会返回“东西”
回答by user113716
It sounds like you want the pathname. If you're in a browser, keep an aelement handy...
听起来你想要pathname. 如果您在浏览器中，请将a元素放在手边...
var _a = document.createElement('a');
...and let it do the parsing for you.
...让它为你做解析。
_a.href = "http://something.com/somethingheretoo";
alert( _a.pathname.slice(1) ); // somethingheretoo
回答by nnnnnn
Try something like the following function, which will return the index of the nth occurrence of the search string s, or -1 if there are n-1 or fewer matches.
尝试类似下面的函数，它将返回搜索字符串 s 第 n 次出现的索引，如果有 n-1 个或更少的匹配项，则返回 -1。
String.prototype.nthIndexOf = function(s, n) {
var i = -1;
while(n-- > 0 && -1 != (i = this.indexOf(s, i+1)));
return i;
}
var str = "some string to test";
alert(str.nthIndexOf("t", 3)); // 15
alert(str.nthIndexOf("t", 7)); // -1
alert(str.nthIndexOf("z", 4)); // -1
var sub = str.substr(str.nthIndexOf("t",3)); // "test"
Of course if you don't want to add the function to String.prototype you can have it as a stand-alone function by adding another parameter to pass in the string you want to search in.
当然，如果您不想将函数添加到 String.prototype 中，您可以通过添加另一个参数来传递您要搜索的字符串，从而将其作为独立函数使用。
回答by Rob W
If you want to stick to indexOf:
如果你想坚持indexOf：
var string = "http://something/sth1/sth2/sth3/"
var lastIndex = string.indexOf("/", lastIndex);
lastIndex = string.indexOf("/", lastIndex);
lastIndex = string.indexOf("/", lastIndex);
string = string.substr(lastIndex);
If you want to get the path of that given URL, you can also use a RE:
如果你想获取给定 URL 的路径，你也可以使用 RE：
string = string.match(/\/\/[^\/]+\/(.+)?/)[1];
This RE searches for "//", accepts anything between "//" and the next "/", and returns an object. This object has several properties. propery [1]contains the substring after the third /.
此 RE 搜索“ //”，接受“ //”和下一个“ /”之间的任何内容，并返回一个对象。这个对象有几个属性。属性[1]包含第三个 之后的子字符串/。
回答by Pat
In your case, you could use the lastIndexOf()method to get the 3rd forward slash.
在您的情况下，您可以使用该lastIndexOf()方法获取第三个正斜杠。
回答by erlingormar
Here's a very cool way of handling this: How can I remove all characters up to and including the 3rd slash in a string?
这是一种非常酷的处理方法： 如何删除字符串中直到并包括第 3 个斜杠的所有字符？
My preference of the proposed solutions is
我对提议的解决方案的偏好是
var url = "http://blablab/test/page.php";
alert(url.split("/")[3]);
//-> "test"
