如何使用 JavaScript 正则表达式提取字符串中的最后一个单词？

Question

I need is the last match. In the case below the word test without the $ signs or any other special character:

Test String:

$this$ $is$ $a$ $test$ 

Regex:

\b(\w+)\b

Answer 1

The $ represents the end of the string, so...

\b(\w+)$

However, your test string seems to have dollar sign delimiters, so if those are always there, then you can use that instead of \\b .

\$(\w+)\$$

 var s = "$this$ $is$ $a$ $test$"; document.body.textContent = /\\$(\\w+)\\$$/.exec(s)[1];

If there could be trailing spaces, then add \\s* before the end.

\$(\w+)\$\s*$

And finally, if there could be other non-word stuff at the end, then use \\W* instead.

\b(\w+)\W*$

Answer 2

In some cases a word may be proceeded by non-word characters, for example, take the following sentence:

Marvelous Marvin Hagler was a very talented boxer!

If we want to match the word boxer all previous answers will not suffice due the fact we have an exclamation mark character proceeding the word. In order for us to ensure a successful capture the following expression will suffice and in addition take into account extraneous whitespace, newlines and any non-word character.

[a-zA-Z]+?(?=\s*?[^\w]*?$)

https://regex101.com/r/D3bRHW/1

We are informing upon the following:

1. We are looking for letters only, either uppercase or lowercase.
2. We will expand only as necessary.
3. We leverage a positive lookahead.
4. We exclude any word boundary.
5. We expand that exclusion,
6. We assert end of line.

The benefit here are that we do not need to assert any flags or word boundaries, it will take into account non-word characters and we do not need to reach for negate.

Answer 3

var input = "$this$ $is$ $a$ $test$";

如果你使用var result = input.match("\\b(\\w+)\\b")接下来将返回所有匹配的数组，你可以通过对结果使用pop()或通过执行以下操作来获取它： result[result.length]

Answer 4

Your regex will find a word, and since regexes operate left to right it will find the first word.

A \\w+ matches as many consecutive alphanumeric character as it can, but it must match at least 1.
A \\b matches an alphanumeric character next to a non-alphanumeric character. In your case this matches the '$' characters.

What you need is to anchor your regex to the end of the input which is denoted in a regex by the $ character.

To support an input that may have more than just a '$' character at the end of the line, spaces or a period for instance, you can use \\W+ which matches as many non-alphanumeric characters as it can:

\$(\w+)\W+$

Answer 5

Avoid regex - use .split and .pop the result. Use .replace to remove the special characters:

var match = str.split(' ').pop().replace(/[^\w\s]/gi, '');

DEMO