正则表达式 - 去除第一个和第二个正斜杠之间的文本

Question

I've almost got this regex working but am having trouble with the leading forward slash - can anyone see where I'm going wrong with this? I just want to extract the first string " projects " from this example

  /projects/personal/29/56

see also here -> http://regexr.com?300av

Answer 1

The easiest way is to split string using forward slash

var firstString = url.split('/')[1];

and you will have first string, but if you want to extract using regext than this will do, just remember don't add global parameter in your regex.

\/([a-zA-Z0-9]{0,})

I hope this helps

Answer 2

I played around with the answer from anubhava and got the following

string                          expression                             returns
/projects/personal/29/56        ([a-zA-Z])([^/]*)\/                     projects/
/projects/personal/29/56        ([a-zA-Z])([^/]*)                       projects
/projects123/personal/29/56     ([a-zA-Z])*?([a-zA-Z][0-9])([^/]*)      projects123

The second line achieves what bsod99 was asking:

• remove the first slash / and
• extract the first string projects from /projects/personal/29/56

Answer 3

It seems you can get your test using split but for pure regex solution use:

s = '/projects/personal/29/56';
arr = s.match(/^\/([^/]*)\//); // arr[1] becomes 'project'
document.writeln('<pre>Matched: [' + arr[1] + "]</pre>");

Answer 4

Adding for someone who comes looking for this kind of answer. You can try adding global flag to get other values also and in addition to the first part of url '/projects'.

/projects/personal/29/56

You just need to traverse the array present at the end [i]

/\/([a-zA-Z0-9]{0,})/g[i]

expression                       returns
i=0                             /projects
i=1                             /personal
i=2                             /29
i=3                             /56

Answer 5

I'm adding the answer here, only because I wanted to add it to [SO]: Python: return a string between // regex , and that question was marked as a dup to this one (!!! while I was editing !!!).

script.py :

#!/usr/bin/env python3

import re


def main():
    group_name = "between_slashes"
    words = [
                "en/lemon_peel/n/",
                "ca/llimona/n/",
                "/asd /",
                "/asd",
                "asdf/",
                "aa//vv",
            ]
    pat = re.compile("^[^/]*/(?P<{}>[^/]*)/.*$".format(group_name))
    for idx, word in enumerate(words):
        match = pat.match(word)
        if match is not None:
            print("{}: \"{}\" - \"{}\"".format(idx, word, match.group(group_name)))
        else:
            print("{}: \"{}\"".format(idx, word))


if __name__ == "__main__":
    main()

Notes :

• The pattern seems complicated, but I'll do my best to explain it:
  1. The 1 ^st char ( ^ ) marks the beginning of the string
  2. The following [] matches a character class: the contents ( ^/ ) tells it to match any character but /
  3. Next, the * tells that the previous group ( #2. ) can occur 0 or more times
  4. Then it follows the / character which is our 1 ^st (begin) guard
  5. The parentheses () denote a group match - which can be later referenced as by its name ( between_slashes ). For more details check [Python 3.Docs]: Regular Expression Syntax (search for (?P<name>...) )
  6. The contents between the parentheses (after > ) are what we are looking for (we already know what): 0 or more non / char s
  7. The next / char is our 2 ^nd (end) guard
  8. Then, .* tells: any char , 0 or more times
  9. Finally, $ marks the end of the string
• I took the liberty of adding more strings to be searched, besides the ones provided in the question, to illustrate some corner cases
• Runs with Python 3 and Python 2

Output :

 c:\\Work\\Dev\\StackOverflow\\q45985002>"c:\\Install\\x64\\Python\\Python\\3.5\\python.exe" script.py 0: "en/lemon_peel/n/" - "lemon_peel" 1: "ca/llimona/n/" - "llimona" 2: "/asd /" - "asd " 3: "/asd" 4: "asdf/" 5: "aa//vv" - ""

Answer 6

在 JS RegEx 中，您可以使用：

\B\/([a-zA-Z0-9-]{0,})\S