Use static string once in Regex while using two patterns with OR

Question

Here is my regex:

STATICSTRING\s[a-zA-Z]:\\[\\\S|*\S]?.*$|STATICSTRING\s\w*

as you can see there are two patterns, \s[a-zA-Z]:\\[\\\S|*\S]?.*$ and \s\w* which is combined with a | operator. and the STATICSTRING is repeated in each one.

Is there any way to write STATICSTRING once?

Use `|` and a grouping construct: `STATICSTRING\s(?:[a-zA-Z]:\\[\\\S|*\S]?.*$|\w*)`. However, `\\[\\\S|*\S]?.*` looks too suspicious. What should it match? — Wiktor Stribiżew, Jun 25 '18 at 07:03

Wiktor Stribiżew · Accepted Answer · 2018-06-25T07:11:29.927

2

You may use an | alternation operator in a grouping construct to group two subpatterns:

STATICSTRING\s(?:[a-zA-Z]:\\[\\\S|*\S]?.*$|\w*)
              ^^^                         ^   ^

However, the \\[\\\S|*\S]?.* part looks like a user error. It matches a \, then 1 or 0 occurrences of \, |, * or any non-whitespace char, and then .* matches any 0+ chars up to the end of the line. Make sure you fix it if you intended to match anything else. But \w* branch will always "win" as it always matches (either an empty string or a letter (and [a-zA-Z] also matches a letter)). So, the pattern above is equal to STATICSTRING\s\w*.

edited Jun 25 '18 at 07:11

answered Jun 25 '18 at 07:07

Wiktor Stribiżew

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the first part is a pattern for file path :) – Inside Man Jun 25 '18 at 07:10
@Nofuzy It is not important, the pattern you have needs a fix. – Wiktor Stribiżew Jun 25 '18 at 07:11
I do not know much about regex, I just copy and paste them from net with my needs. could you give the fixed one? – Inside Man Jun 25 '18 at 07:12
@Nofuzy No idea, I do not know what you really need. – Wiktor Stribiżew Jun 25 '18 at 07:12
my goal is to capture both `static c:\file\name.txt` or `static sdfsfdf` – Inside Man Jun 25 '18 at 07:13
To match anything, just use `.*`, there is no precise pattern for file paths. In Unix/Linux, file names can contain any character. For Windows file paths, you can use [this regex](https://stackoverflow.com/questions/24702677/regular-expression-to-match-a-valid-absolute-windows-directory-containing-spaces). – Wiktor Stribiżew Jun 25 '18 at 07:13
`\w*` with not capture for `:` or `\` characters – Inside Man Jun 25 '18 at 07:13
it is more than matching anything. because I'm replacing it with something else and there are several other parts in my whole string. If I match anything then replacing it, the whole string will destroyed :) – Inside Man Jun 25 '18 at 07:15
You cannot rely on `\S*`, but it seems the only work around for you. It will match 0+ non-whitespace chars. Something like `STATICSTRING\s+\S+` – Wiktor Stribiżew Jun 25 '18 at 07:16
just tell if `[a-zA-Z]:\\[\\\S|*\S]?.*$` suitable for matching file path in windows or not? :) – Inside Man Jun 25 '18 at 07:17
1

`[a-zA-Z]:\\[\\\S|*\S]?.*$` = `[a-zA-Z]:\\\S.*$`, and it matches a letter, ``:\``, then any char other than whitespace and then any 0+ chars to the end of the line. No, it is not. – Wiktor Stribiżew Jun 25 '18 at 07:19
`[a-zA-Z]:\\\S.*$` and mine will continue matching after the file extension too. it is the right match `C:\t.txt` but this one is wrong which currently is matched also `C:\t.txt ttt`. any advice or edit? – Inside Man Jun 25 '18 at 07:26
@Nofuzy There is no regex to match valid file paths. – Wiktor Stribiżew Jun 25 '18 at 07:27
I need to see only one `.` char and after that there should not exist a space char and only simple chars. – Inside Man Jun 25 '18 at 07:29
1

Well, try `[a-zA-Z]:(?:\\[^\/]+)*\\.*?\.\S+` or even `[a-zA-Z]:\\.*?\.\S+` but no one guarantees that it won't over-match in case there is a no-match and a match on a single line. – Wiktor Stribiżew Jun 25 '18 at 07:31
Works like a charm ;) – Inside Man Jun 25 '18 at 07:48

Use static string once in Regex while using two patterns with OR

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