a regex question. help needed

[FlyBoy]

i have the following pattern:
([\w\-]+\.)+
([\w\-]{2,3})

which should validate a hostname adress.
i cand understan some parts of it.
i know that the \w represents and "word" chaaracter.
but what the \- does???????

 

[John_0025]

Its a hyphen - so matches the hyphen in Xtreme-talk.com

In regular expressions the hyphen is used to show a range of allowed characters. i.e. 0-8 (matchs 0,1,2,3,4,5,6,7,8) so you have to show that you want to match a hyphen and you are not using it as a special character therefor you need to put the \ symbol in from.

[A-Z] matchs any letter but [e\-t] matchs the hyphen and will find matchs with e-t in only. like in Xtreme-talk.
Hope this makes sense.

 

[FlyBoy]

Its a hyphen - so matches the hyphen in Xtreme-talk.com

In regular expressions the hyphen is used to show a range of allowed characters. i.e. 0-8 (matchs 0,1,2,3,4,5,6,7,8) so you have to show that you want to match a hyphen and you are not using it as a special character therefor you need to put the \ symbol in from.

[A-Z] matchs any letter but [e\-t] matchs the hyphen and will find matchs with e-t in only. like in Xtreme-talk.
Hope this makes sense.

10x for the reply!
this pattern as i said before matches to host names such as : www.contoso.com


i dont see any hyphen in here. still cant understand this hyphen thingy.

if i had to rewrite this pattern i would do it like this:
(\w{3}\.)+(\w (2,3)

and i guess its wrong.

 

[John_0025]

Some domain name do have the hyphen in and the expression you were using was to try and match all of them.

If you are sure there will never be a hyphen in the name you are trying to match then you can miss it out.

([\w]+\.)+([\w]{2,3})

which will match www.contoso.com but it wont match a website called www.j-walk.com. Your original pattern would.

I see what you are trying to do with your pattern. Maybe it might help you to start of with a simple pattern that will match your example. Then see how you would change it to deal with other host names.

Try

www.[a-z]{1,}.[a-z]{2,3}

 

[FlyBoy]

Some domain name do have the hyphen in and the expression you were using was to try and match all of them.

If you are sure there will never be a hyphen in the name you are trying to match then you can miss it out.

([\w]+\.)+([\w]{2,3})

which will match www.contoso.com but it wont match a website called www.j-walk.com. Your original pattern would.

I see what you are trying to do with your pattern. Maybe it might help you to start of with a simple pattern that will match your example. Then see how you would change it to deal with other host names.

Try

www.[a-z]{1,}.[a-z]{2,3}

10x mate! now i uderstand it! ! ! many 10x