JS gets the position of the nth occurrence of the specified string in a string

1.JS gets the position of the nth occurrence of the specified string in a string

Learn similar ways to get character positions:

1.1 charAt () Gets the character of the string at the specified position

Usage: Strobj is a String object, index is the specified position, (position starting from 0)

Strobj.charat (Index)

　　

The 1.2 indexOf () method returns the position of the first occurrence of a specified string value in a string

Usage: Stringobject is a string object, Searchvalue is the specified string value, and Fromindex (optional) specifies the position at which to start matching the string value, if none, that is, starting at the 0 position.

Stringobject.indexof (Searchvalue,fromindex)

　　Cases:

var str= ' HelloWorld '; var num=str.indexof (' O '); // returns 4

2. The subject

Gets a string value where the nth occurrence of the specified string

Just like the example above, Helloword, I want to get the second o where it appears

JS Code: Parameter (string, to find the string value, to find the number of the string value

  function Find (str,cha,num) {    var x=str.indexof (cha);      for (var i=0;i<num;i++) {        x=str.indexof (cha,x+1);    }     return x;    }

　　To refer to this method:

Ar str= "Hello world!" document.write (Find (str,' O ', 2)); // returns 7

The basic usage is this, for a string of the same character than characters string, only need to change the corresponding 2 for the n value you want to find it.

For example, get the location where nth '/' appears in the URL of the current page

Call the above method directly

AR str=document. url;//Gets the full path information of the current page document.write (Find (str,'/', n));

Get the page path method, refer to my next article:

JS gets the position of the nth occurrence of the specified string in a string