Regular Expression to detect a file extension

Question

I need a regular expression that will detect a filename from a string - see if it ends with .pdf, or .PDF - case insensitive. Should even match .Pdf or any variant of pdf in case the user has messy filenames.

This will be used in PHP 5. I know I can make a bunch of rows to test against each case, but I'm sure there's a more elegant way to do this.

Answer 1

正则表达式没有任何问题，但是还有一个现成的函数用于剖析路径并从中提取扩展：

echo pathinfo("/path/to/myfile.txt", PATHINFO_EXTENSION); //.txt

Answer 2

how about this one. I dont know what language you are using but here is a regex for matching anything ending in .pdf

.+([.][Pp][Dd][Ff]){1}

my bad. Im half asleep. PHP it is. dont know php but that regex should work

Answer 3

另一种可能性是延长

strtolower(pathinfo("/path/file.pDf", PATHINFO_EXTENSION)) == ".pdf"

Answer 4

正如其他人所说，提取扩展名会有效，否则你可以做这样的事情。

preg_match('/.*\\.pdf/i', "match_me.pDf", $matches);

Answer 5

If your string consists of a single filename here is a simple regex solution:

if (preg_match('/\.pdf$/i', $filename)) {
   // Its a PDF file
}