切掉一部分字符串

Question

说,我有一个字符串

"hello is it me you're looking for"

我想删除这个字符串的一部分并返回新字符串,类似于

s = string.cut(0,3);

s现在等于:

"lo is it me you're looking for"

编辑:它可能不是从0到3.它可能是5到7.

s = string.cut(5,7);

会回来的

"hellos it me you're looking for"

Answer 1

你快到了.你想要的是:

http://www.w3schools.com/jsref/jsref_substr.asp

所以,在你的例子中:

Var string = "hello is it me you're looking for";
s = string.substr(3);

因为只提供一个开始(第一个arg)从该索引到字符串的结尾.

更新,如下:

function cut(str, cutStart, cutEnd){
  return str.substr(0,cutStart) + str.substr(cutEnd+1);
}

Answer 2

使用

子

功能

返回一个索引与另一个索引之间或字符串末尾的字符串子集.

substring(indexA, [indexB]);

指数A

An integer between 0 and one less than the length of the string. 

indexB (可选)0到字符串长度之间的整数.

substring从indexA中提取字符,但不包括indexB.特别是:

* If indexA equals indexB, substring returns an empty string.
* If indexB is omitted, substring extracts characters to the end 
  of the string.
* If either argument is less than 0 or is NaN, it is treated as if 
  it were 0.
* If either argument is greater than stringName.length, it is treated as 
  if it were stringName.length.

如果indexA大于indexB,那么substring的效果就好像交换了两个参数; 例如,str.substring(1,0)== str.substring(0,1).

Answer 3

其他一些更现代的替代方案是：

1. 分裂和加入

   function cutFromString(oldStr, fullStr) {
     return fullStr.split(oldStr).join('');
   }
   cutFromString('there ', 'Hello there world!'); // "Hello world!"
   

   _{改编自MDN 示例}

2. String.replace()，它使用正则表达式。这意味着它可以更加灵活地区分大小写。

   function cutFromString(oldStrRegex, fullStr) {
     return fullStr.replace(oldStrRegex, '');
   }
   cutFromString(/there /i , 'Hello THERE world!'); // "Hello world!"