如何用範圍替換字符串？

Question

我需要範圍 實施例替換字符串：

string = "this is a string";//I need to replace index 0 to 3 whith another string Ex.:"that" 
result = "that is a string"; 

但這種需要是dinamically。不能被取代固定字...需要時可使用範圍

我已經試過

  result = string.replaceAt(0, 'that'); 

但這僅替換第一個字符，我想第一至第三

Answer 1

function replaceRange(s, start, end, substitute) { 
    return s.substring(0, start) + substitute + s.substring(end); 
} 

var str = "this is a string"; 
var newString = replaceRange(str, 0, 4, "that"); // "that is a string" 

Answer 2

var str = "this is a string"; 
var newString = str.substr(3,str.length); 
var result = 'that'+newString 

SUBSTR回報一個字符串的一部分，用我的例子，它開始於字符3到str.length以具有最後一個字符...

要替換字符串的中間，可以使用相同的邏輯...

var str = "this is a string"; 
var firstPart = str.substr(0,7); // "this is " 
var lastPart = str.substr(8,str.length); // " string" 
var result = firstPart+'another'+lastPart; // "this is another string" 

Answer 3

我簡單substring電話將在這裏做

var str = "this is a string"; 
var result = "that" + str.substring(4); 

退房工作jsfiddle。