JS intercept and split string common skills summary _javascript skills

This article illustrates the common methods for JS intercepting and segmenting strings. Share to everyone for your reference, specific as follows:

JS intercept string can use substring () or slice ()

function: substring ()

Definition: substring (start,end) represents a string from start to end, including characters from the start position but not the end position.

Function: string interception, for example, to get "Minidx" from "minidxsearchengine" to use SUBSTRING (0,6)

Example:

var src= "Images/off_1.png";
Alert (src.substring (7,10));
The pop-up value is: off

Function: substr ()

Definition: substr (start,length) indicates that the length of a string is intercepted from the start position.

Function: String interception

Example:

var src= "Images/off_1.png";
Alert (SRC.SUBSTR (7,3));
The pop-up value is: off

Function: Split ()

Function: To store a string partition into an array using a specified delimiter

Example:

Str= "Jpg|bmp|gif|ico|png";
Arr=thestring.split ("|");
Arr is an array that contains the character values "JPG", "BMP", "GIF", "ico", and "PNG"

Function: John ()

Function: Merges an array into a string using the separator of your choice

Example:

var delimitedstring=myarray.join (delimiter);
var mylist=new Array ("JPG", "BMP", "GIF", "ico", "PNG");
var portablelist=mylist.join ("|");
The result is jpg|bmp|gif|ico|png.

Function: IndexOf ()

Function: Returns the subscript of the first character in a string that matches a substring

var mystring= "JavaScript";
var w=mystring.indexof ("V"); W'll be 2
var x=mystring.indexof ("S"); x'll be is 4
var y=mystring.indexof (" Script "); y'll also be 4
var z=mystring.indexof (" key "); Z'll be-1 

Function: LastIndexOf ()

Definition: LastIndexOf () method returns the first character index value of a character or string that appears from right to left (contrary to indexof)

Function: return string index value

Example:

var src= "Images/off_1.png";
Alert (Src.lastindexof ('/'));
Alert (Src.lastindexof (' G '));
The pop-up values, in turn, are: 6,15

Add: The difference between substr and substring methods

Substr method

Returns a substring of the specified length starting at the specified position.

Stringvar.substr (start [, length])

Parameters

Stringvar

Required option. The string literal or string object to extract the substring.

Start

Required option. The starting position of the desired substring. The index of the first character in the string is 0.

Length

Options available. The number of characters that should be included in the returned substring.

Description

If length is 0 or negative, an empty string is returned. If this argument is not specified, the substring continues to the end of the stringvar.

Example

The following example shows the use of the Substr method.

function Substrdemo () {
  var s, SS;        Declare a variable.
  var s = "The rain in Spain falls mainly in the plain.";
  SS = S.substr (12, 5); Gets the substring. Return
  (ss);        Returns "Spain".
}

Substring method

Returns a substring at the specified position in a string object.

Strvariable.substring (start, end)
"String Literal". Substring (start, end)

Parameters

Start

Indicates the starting position of the substring, starting at 0.

End

Indicates the end position of the substring, starting at 0.

Description

The substring method returns a string containing a substring from start to the last (not including end).

The substring method uses the smaller values in both start and end as the starting point for substrings. For example, strvar.substring (0, 3) and strvar.substring (3, 0) will return the same substring.

If start or end is NaN or negative, replace it with 0.

The length of the substring equals the absolute value of the difference between start and end. For example, the length of the substring returned in strvar.substring (0, 3) and strvar.substring (3, 0) is 3.

Example

The following example shows the use of the substring method.

function Substringdemo () {
  var ss;//Declaration variable.
  var s = "The rain in Spain falls mainly in the plain ...";
  SS = S.substring (12, 17); Takes a substring.
  return (ss);//back substring.
}

I hope this article will help you with JavaScript programming.