RegExp - Is this correct?

[Steveiwonder]

Hey all,

Didn't want to ask for someone to just do what i needed but can someone atleast confirm if i'm right/wrong. I'd like to point out RegExp's blow my brain!

Firstly "$id" must be a combination of exactly 10 random numbers. Would the below work?

(Yes i know how simple it is for you guru's, i just simply fail at Regular Expressions)

$id = "2003714598"

If StringRegExp($id, '\b[0-9]{10}\b') Then
    MsgBox(0, "Match", $id & " Found")
Else
    MsgBox(0, "No Match", $id & " Not Found")
EndIf

And also this one..

Has to match the start of the URL and then 7 random digits then the end of the URL.

$url = "https://somerandomwebsite.ams.uk.com/details.php?i=1245795&t=d"

If StringRegExp($url,"[https://somerandomwebsite.ams.uk.com/details.php?i=][0-9]{7}[&t=d]") Then
    MsgBox(0, "Match", $url & " Found")
Else
    MsgBox(0, "No Match", $url & " Not Found")
EndIf

I would just like to know weather i have mastered (as far as my brain will allow) the art of Regular Expressions or can it be done another way.

Thanks

Steve

Edited February 2, 2010 by Steveiwonder

[Bowmore]

Your first RegEx pattern appears to be correct if you want to match a word that consists of exactly 10 numbers.

There is an error with your second RegEx pattern. You should remove the [] from around the first part of the URL. As it is it will only match one of the characters between the square brackets and I assume that you want to match the whole of the first part of the URL. Also the last bit should not be enclosed by [] 

 

 

Edited February 2, 2010 by Bowmore

[jchd]

Let me expand a bit on the good answer already provided.

You may also use \d in place of [0-9] to match a (decimal) digit. So your first reg. expression can be '\b\d{10}\b' equivalently. This is only a handy shorthand.

\b matches a "word boundary" so the regexp above means "I match if I find a sequence of 10 decimal digits surrounded by whitespaces or begin/end of string"

Hence '\b\d{10}\b' will hapily match 'gfhuo nio rzjlik hre 0123456789 blbdn lk'

But

If you want to enforce the rule that your input "must be a combination of exactly 10 random numbers" then the first regexp isn't exactly what you need, as the example above shows.

Make your regexp '\A\d{10}\z', meaning "I match if the string contains exclusively a sequence of 10 decimal digits." This one leaves no room for chance.

You see on this simple example that you can and probably should match precisely what you intent, nothing less but nothing more.

For instance, what would you choose: "I say that the code is 0123456789 ... OMG, I made a horrible mistake: the actual code is 9876543210 forgive me dear fellow!"

The first regexp will happily pick 0123456789 but the second one will bark, giving you the opportunity to catch the error.

In short: regexp are very powerful and offer means to express precise conditions. When you use them routinely choose the right balance between being pointlessly too strict and lazily too permissive. Anyway, regexp will bring you joy and frustration, just like a real-life partner.

EDIT: a couple of typos, my bad.[really bad, yet another: [0-9] = \d not \b of course. Thanks Trancexx!]

Edited February 3, 2010 by jchd

[Steveiwonder]

I think i may be confusing myself...

Without the [] it doesnt find match, but with it does.

Local $oLinks[6]
$oLinks[0] = "wadad"
$oLinks[1] = "awdawd"
$oLinks[2] = "354345$%@$%$:%@£$5"
$oLinks[3] = "fewdawda.com wdwad23423 "
$oLinks[4] = "https://randomsite.com/roooar/details.php?i=7548924&t=d"
$oLinks[5] = "wddadd33444444322&&*&*£$%£"

$pattern = "https://randomsite.com/roooar/details.php?i=[0-9]+&t=d"
;$pattern = "[https://randomsite.com/roooar/details.php?i=][0-9]+[&t=d]"

For $oLink in $oLinks
        
        If StringRegExp($oLink, $pattern) then 
            ;_IENavigate($oIE, $oLink)
            Msgbox(0,"Match", "Match Found")
            ExitLoop            
        EndIf       
Next

Thanks for both replies.

Steve

[Steveiwonder]

I think i may be confusing myself...

Without the [] it doesnt find match, but with it does.

Local $oLinks[6]
$oLinks[0] = "wadad"
$oLinks[1] = "awdawd"
$oLinks[2] = "354345$%@$%$:%@£$5"
$oLinks[3] = "fewdawda.com wdwad23423 "
$oLinks[4] = "https://randomsite.com/roooar/details.php?i=7548924&t=d"
$oLinks[5] = "wddadd33444444322&&*&*£$%£"

$pattern = "https://randomsite.com/roooar/details.php?i=[0-9]+&t=d"
;$pattern = "[https://randomsite.com/roooar/details.php?i=][0-9]+[&t=d]"

For $oLink in $oLinks
        
        If StringRegExp($oLink, $pattern) then 
            ;_IENavigate($oIE, $oLink)
            Msgbox(0,"Match", "Match Found")
            ExitLoop            
        EndIf       
Next

Thanks for both replies.

Steve

I worked out what im doing wrong i think...

I needed to escape some special characters? So the pattern i now have is this..

$pattern = "https\://randomsite\.com/roooar/details\.php\?i=[0-9]+&t=d"

Am i on the right track?

Edited February 3, 2010 by Steveiwonder

[Melba23]

Steveiwonder,

You have it.

M23

[Steveiwonder]

Woop! Now anyone who needs help with RegExp's just throw them my way i have mastered the art!

On a serious note, thanks everyone

Edited February 3, 2010 by Steveiwonder

[Melba23]

Steveiwonder,

Woop! Now anyone who needs help with RegExp's just throw them my way i have mastered the art!

Dream on........

M23

[trancexx]

...

EDIT: a couple of typos, my bad.

You changed a but you forgot to change b.

Nice post, btw.

[jchd]

You changed a but you forgot to change b.

Oops, Good catch. That's age + no sleep.

It was a good opportunity to have the OP's -and possibly some readers'- curiosity stimulated so that they dig further into regexp.

In a while, OP and other will routinely write working "serious" regexps, just like this one, which will match any form of valid email address:

This is page 316 of Jefferey' book Mastering Regular Expressions ed.1 (I didn't find it in text form on the Internet)