File Extension Extraction Regex
Extract file extensions from filenames. Matches extensions like .pdf, .jpg, .txt at the end of filenames.
Pattern & Test String
About This Pattern
Pattern: \.[a-zA-Z0-9]+$
Flags: g
Results
Enter a regex pattern to see the results here.
Frequently Asked Questions
Does this handle multiple dots in filenames?
Yes, this pattern matches only the last extension. For 'archive.tar.gz', it matches '.gz'. To match '.tar.gz', use a more specific pattern.
What about files without extensions?
This pattern won't match files without extensions. Check if the pattern matches before assuming an extension exists.
How do I validate specific file types?
Modify the pattern: \.(pdf|jpg|png|doc)$ to match only specific extensions.
Practical Examples
File Upload Validation
Extract and validate file extensions during file uploads.
File Organization
Group or sort files by extension type.
MIME Type Detection
Extract extensions to determine MIME types for file handling.
Common Issues & Solutions
To extract without the dot, use a capture group: \.([a-zA-Z0-9]+)$ and access the captured group.
For case-insensitive matching (treating .PDF and .pdf the same), enable the 'i' flag.
This pattern doesn't validate if the extension is valid or recognized. Check against a whitelist of allowed extensions.
Hidden files starting with dot (.gitignore) may cause issues. Add logic to check for this case.