Asp Forum
Home
|
Login
|
Register
|
Search
Forums
>
comp.lang.ruby
regular expression
David Nguyen
8/6/2008 2:27:00 PM
Hi,
I need a regular expression for a filename :
it must be composed with the following letters :
a to z
A to Z
0 to 9
dash sign -
underscore sign _
then how can I compare a string with it :
mystring =~ /myregex/ #return true or false
does it works like that ?
--
Posted via
http://www.ruby-...
.
1 Answer
Rob Biedenharn
8/6/2008 2:53:00 PM
0
On Aug 6, 2008, at 10:26 AM, David Nguyen wrote:
> Hi,
> I need a regular expression for a filename :
> it must be composed with the following letters :
>
> a to z
> A to Z
> 0 to 9
> dash sign -
> underscore sign _
>
> then how can I compare a string with it :
>
> mystring =~ /myregex/ #return true or false
>
> does it works like that ?
Yes. Although String#=~ returns the position the match starts, or nil
if there is no match. If the right-hand-side is not a Regexp, invokes
obj.=~, passing str as an argument. The default =~ in Object returns
false.
Since a Fixnum is not nil or false, it will be "true" and both nil and
false will be "false".
The only other issue is that the dash (hyphen-minus; '-') is special
inside a character class of regular expressions. For example, if you
wanted to match a dash or digit, you could use /[-0-9]/ so the -
appearing first is not treated as a character range operation.
-Rob
Rob Biedenharn
http://agileconsult...
Rob@AgileConsultingLLC.com
Servizio di avviso nuovi messaggi
Ricevi direttamente nella tua mail i nuovi messaggi per
regular expression
Inserendo la tua e-mail nella casella sotto, riceverai un avviso tramite posta elettronica ogni volta che il motore di ricerca troverà un nuovo messaggio per te
Il servizio è completamente GRATUITO!
x
Login to ForumsZone
Login with Google
Login with E-Mail & Password