Javascript：獲取字符串的最後幾個字符

Question

如果我們將字符串存儲在變量中，這是一個微不足道的問題。但出於好奇，我需要了解如何實現這一點，而不需要在變量中存儲字符串？

// To get first few characters of a string, we can do something like this: 
var x = "amangupta".substring(0,7); //amangup 

// How to get last 7 characters 
var x = "amangupta".substring(this.length - 7, this.length); // does not work, looking for similar approach 

var str = "amangupta"; 
var x = str.substring(str.length - 7, str.length); // will work fine 

Answer 1

如何最後7個字符

嘗試

"amangupta".slice(-7) 

Answer 2

獲得沒有你需要使用字符串一個額外的變量再次

"amangupta".substring("amangupta".length - 7, "amangupta".length);