(轉)jQuery String Functions

In today's post, I have put together all jQuery String Functions. Well, I should say that these are not "jQuery String Functions". These are "JavaScript String Functions". But as jQuery is built on top of JavaScript so you can use them with jQuery as well. So I call them "jQuery String Functions".

Earlier I had posted about jQuery solution to split string, replace string, substring and trim string And In this post, see all jQuery/JavaScript string functions in action with examples.

Related Post:

• Common utility methods of jQuery
• Common jQuery Mistakes

• charAt(n): Returns the character at the specified index in a string. The index starts from 0.
  
   

  1	var str = "JQUERY By Example";

  2	var n = str.charAt(2)

  3

  4	//Output will be "U"

• charCodeAt(n): Returns the Unicode of the character at the specified index in a string. The index starts from 0.
  
   

  1	var str = "HELLO WORLD";

  2	var n = str.charCodeAt(0);

  3

  4	//Output will be "72"

• concat(string1, string2, .., stringX): The concat() method is used to join two or more strings. This method does not change the existing strings, but returns a new string containing the text of the joined strings.
  
   

  1	var str1 = "jQuery ";

  2	var str2 = "By Example!";

  3	var n = str1.concat(str2);

  4

  5	//Output will be "jQuery By Example!"

• fromCharCode(n1, n2, ..., nX): Converts Unicode values into characters. This is a static method of the String object, and the syntax is always String.fromCharCode().
  
   

  1	var n = String.fromCharCode(65);

  2

  3	//Output will be "A"

• indexOf(searchvalue, [start]): Returns the position of the first occurrence of a specified value in a string. This method returns -1 if the value to search for never occurs. This method is case sensitive!
  
   

  1	var str="Hello world, welcome to the my blog.";

  2	var n=str.indexOf("welcome");

  3

  4	//Output will be "13"

• lastIndexOf(searchvalue, [start]): Returns the position of the last occurrence of a specified value in a string. The string is searched from the end to the beginning, but returns the index starting at the beginning, at postion 0. Returns -1 if the value to search for never occurs. This method is case sensitive!
  
   

  1	var str="Hello planet earth, you are a great planet.";

  2	var n=str.lastIndexOf("planet");

  3

  4	//Output will be "36"

• substr(start, [length]): The substr() method extracts parts of a string, beginning at the character at the specified posistion, and returns the specified number of characters.
  
   

  1	var str="Hello world!";

  2	var n=str.substr(2,3)

  3

  4	//Output will be "llo"

• substring(from, [to]): The substring() method extracts the characters from a string, between two specified indices, and returns the new sub string. This method extracts the characters in a string between "from" and "to", not including "to" itself.
  
   

  1	var str="Hello world!";

  2	var n=str.substring(2,3)

  3

  4	//Output will be "l"

• toLowerCase(): The toLowerCase() method converts a string to lowercase letters.
  
   

  1	var str="HELLO WoRld!";

  2	str = str.toLowerCase();

  3	//Output will be "hello world!"

• toUpperCase(): The toUpperCase() method converts a string to uppercase letters.
  
   

  1	var str="hello WoRLd!";

  2	str = str.toUpperCase();

  3	//Output will be "HELLO WORLD!"

  Also read "jQuery Code: Change text to Uppercase"
  
  Download plugin for Uppercase, lowercase, title case & pascal case
• match(regexp): The match() method searches a string for a match against a regular expression, and returns the matches, as an Array object.
  
   

  1	var str="The rain in SPAIN stays mainly in the plain";

  2	var n=str.match(/ain/g);

  3

  4	//Output will be "ain,ain,ain"

  5	//There are 3 matches with the "ain" regex in small letters. So it returns ain 3 times.

• replace(searchvalue, newvalue): The replace() method searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced.
  
   

  1	var str="Visit jQuery Blog!";

  2	var n = str.replace("jQuery ","jQuery By Example ");

  3

  4	//Output will be "Visit jQuery By Example Blog!"

• search(searchvalue): The search() method searches a string for a specified value, or regular expression, and returns the position of the match. This method returns -1 if no match is found.
  
   

  1	var str="Visit jQuery Blog!";

  2	var n = str.search("jQuery");

  3

  4	//Output will be "6"

• slice(start, [end]): The slice() method extract parts of a string and returns the extracted parts in a new string. Use the start and end parameters to specify the part of the string you want to extract. The first character has the position 0, the second has position 1, and so on.
  
   

  1	var str="Visit jQuery Blog!";

  2	var n = str.slice(6,12);

  3

  4	//Output will be "jQuery"

• split(separator, [limit]): Read Split function in jQuery

Feel free to contact me for any help related to jQuery, I will gladly help you.

 

Posted by jQueryByExample

-----------------------------------------------我是華麗的分割線----------------------------------------------------

 

在javascript、Jquery裡面好像是沒有String.format();這個函式的，所以我們在拼接字串的時候就特別的辛苦，生怕又打錯，而且又亂，所以就自己去寫一個函式來代替。

String.format = function() {

    if (arguments.length == 0)

        return null;

    var str = arguments[0];

    for ( var i = 1; i < arguments.length; i++) {

        var re = new RegExp('\\{' + (i - 1) + '\\}', 'gm');

        str = str.replace(re, arguments[i]);

    }

    return str;

};

// var a = "我喜歡吃{0}，也喜歡吃{1}，但是最喜歡的還是{0},偶爾再買點{2}";

// alert(String.format(a, "蘋果","香蕉","香梨"));

// 結果:我喜歡吃蘋果，也喜歡吃香蕉，但是最喜歡的還是蘋果,偶爾再買點香梨

是從0位開始的。

建議自己把這些東西寫進一個js檔案，每次使用就呼叫可以了