Javascript正则表达式取代“拆分”

Question

I would like to use Javascript Regex instead of split .

Here is the example string:

var str = "123:foo";

The current method calls:

str.split(":")[1]

This will return "foo" , but it raises an Error when given a bad string that doesn't have a : .

So this would raise an error:

var str = "fooblah";

In the case of "fooblah" I'd like to just return an empty string .

This should be pretty simple, but went looking for it, and couldn't figure it out. Thank you in advance.

Answer 1

Remove the part up to and including the colon (or the end of the string, if there's no colon):

"123:foo".replace(/.*?(:|$)/, '')    // "foo"
"foobar" .replace(/.*?(:|$)/, '')    // ""

How this regexp works:

.*                 Grab everything
?                  non-greedily
(                  until we come to
  :                a colon
  |                or 
  $                the end of the string
)

Answer 2

A regex won't help you. Your error likely arises from trying to use undefined later. Instead, check the length of the split first.

var arr = str.split(':');
if (arr.length < 2) {
  // Do something to handle a bad string
} else {
  var match = arr[1];
  ...
}

Answer 3

Here's what I've always used, with different variations; this is just a simple version of it:

function split(str, d) {
    var op = "";
    if(str.indexOf(d) > 0) {
        op = str.split(d);
    }
    return(op);
}

Fairly simple, either returns an array or an empty string.

Answer 4

 var str1 = "123:foo", str2 = "fooblah"; var res = function (s) { return /:/.test(s) && s.replace(/.*(?=:):/, "") || "" }; console.log(res(str1), res(str2)) 

Answer 5

这是使用单个正则表达式的解决方案，您需要将其包含在捕获组中：

^[^:]*:([^:]+)