CODEWITHSUNDEEP
rubyregex
Starkers
Starkers

Reputation: 10541

Use conditional regex to generate filenames from url

How can I get the following strings to output the following?

regex = '' # help me out here guys!

'baz/foobaryfobar/'.match(regex) #=> foobaryfobar

'baz/foobar'.match(regex) #=> foobar

'baz/foobar.jpg'.match(regex) #=> foobar

'baz/foobar.png'.match(regex) #=> foobar

'baz/foobar.gif'.match(regex) #=> foobar

'baz/foobar.jpeg'.match(regex) #=> foobar

Can it be done with one regex?

update

Non-regex solutions to this more than welcome!

Upvotes: 1

Views: 72

Answers (2)

user557597
user557597

Reputation:

Not sure of the constraints, but maybe one of these

The dot is problematic in your description if it can be part of like file.name.ext
Otherwise,

Gets the filename in capture group 1 - 

 # ([^/.]+)(?:\.[^/.]*|/)?\s*$

 ( [^/.]+ )       # (1)
 (?:
      \. [^/.]* 
   |  /  
 )?
 \s* 
 $

This uses lookahead, the match is the filename - 

 # [^/.]+(?=(?:\.[^/.]*|/)?\s*$)

 [^/.]+ 
 (?=
      (?:
           \. [^/.]* 
        |  /  
      )?
      \s* 
      $ 
 )

Perl test case 

my @ary = (
'baz/foobaryfobar/',
'baz/foobar',
'baz/foobar.jpg',
'baz/foobar.png',
'baz/foobar.gif',
'baz/foobar.jpeg'
);


for $url ( @ary )
{
      if ( $url =~ /[^\/.]+(?=(?:\.[^\/.]*|\/)?\s*$)/ ) {
           print "matched:  $&\n";
      }
}

Output >> 

matched:  foobaryfobar
matched:  foobar
matched:  foobar
matched:  foobar
matched:  foobar
matched:  foobar

Upvotes: 0

Arup Rakshit
Arup Rakshit

Reputation: 118261

How about without Regex, but using extname, basename ?

def gen_file_name(string)
  File.basename(string,File.extname(string))
end

gen_file_name('baz/foobar.jpg') # => "foobar"
gen_file_name("baz/foobaryfobar/") # => "foobaryfobar"
gen_file_name('baz/foobar') # => "foobar"

Upvotes: 3

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