regex101: PCRE2 (PHP) Match Workspace

Regular Expression

^(file:\/\/\/)?(?<root>[a-zA-Z][:|\|])

New

file:///C:/Users/username/example.txt
Matches:
Group 'root': C:
Windows URI without File Protocol:

C:\Projects\file.txt
Matches:
Group 'root': C:
Windows URI with Forward Slashes:

file:///D:/Data/Documents/test.docx
Matches:
Group 'root': D:
Windows URI with Different Drive Letter:

E:\Photos\vacation.jpg
Matches:
Group 'root': E:
Windows URI with Special Characters:

file:///F:/My%20Documents/report.pdf
Matches:
Group 'root': F:
Windows URI with Vertical Bar Separator:

file:///G:|/Movies/action.mp4
Matches:
Group 'root': G:

Does not match:
\Users\username\file.txt
file:///A@:/path/to/file.txt
http://example.com/path/to/file.txt

Extraction

file:///C:/Users/username/example.txt
Matches:
Group 'root': C:
Windows URI without File Protocol:

C:\Projects\file.txt
Matches:
Group 'root': C:
Windows URI with Forward Slashes:

file:///D:/Data/Documents/test.docx
Matches:
Group 'root': D:
Windows URI with Different Drive Letter:

E:\Photos\vacation.jpg
Matches:
Group 'root': E:
Windows URI with Special Characters:

file:///F:/My%20Documents/report.pdf
Matches:
Group 'root': F:
Windows URI with Vertical Bar Separator:

file:///G:|/Movies/action.mp4
Matches:
Group 'root': G:

Does not match:
\Users\username\file.txt
file:///A@:/path/to/file.txt
http://example.com/path/to/file.txt