[C#] Why does this regex not work?

C

Coron

Newbie

Jan 13, 2012

22

0

• Jan 14, 2012

• #1

I'm pretty tired and I've probably missed something, but why does the regex below not work?

Code:

            Regex captchaRegex = new Regex("src=\"example/Captcha?ctoken=(.*?)\"");
            Match captchaMatch = captchaRegex.Match("<img src=\"example/Captcha?ctoken=Get this\" width=\"200\" height=\"70\" alt=\"Visual verification\">");

In case you're wondering, I'm trying to get the captcha image on Google. It doesn't match, I don't get it!!

Also I had to replace an URL in the code with 'example' because I'm new.

 

A

a_z_0_9

Junior Member

Jul 18, 2011

111

21

• Jan 14, 2012

• #2

Try this regex
<img.+?src=[\"']example/Captcha\?ctoken=(.+)?[\"']>

 

A

a_z_0_9

Junior Member

Jul 18, 2011

111

21

• Jan 14, 2012

• #3

try this updated
<img.+?src=[\"']example/Captcha\?ctoken=(?<val>.+)?[\"'] width=["](.*)?["] height=["](.*)?["] alt=["](.*)?["]>

then you can get the value using captchaMatch.Groups["val"].Value

 

C

Coron

Newbie

Jan 13, 2012

22

0

• Jan 14, 2012
• Thread Starter Thread Starter

• #4

a_z_0_9 said:

Try this regex
<img.+?src=[\"']example/Captcha\?ctoken=(.+)?[\"']>

Click to expand...

Thanks for the reply. After changing example to my URL it didn't work. I'm very unfamiliar with regex and I'm not sure if I need to add brackets to the URL as well?

Here is the full regex:
src="hxxxx://accounts.google.xxx/Captcha?ctoken=(.*?)"

edit: I'll try your new reply

 

kaidoristm

BANNED

Feb 13, 2009

564

732

• Jan 14, 2012

• #5

Escape ? in your regex

 

A

a_z_0_9

Junior Member

Jul 18, 2011

111

21

• Jan 14, 2012

• #6

try this updated one for actual source
<img.+?src=[\"'].*?\?ctoken=(?<val>.+)?[\"'] width=["](.*)?["] height=["](.*)?["] alt=["](.*)?["]>

captchaMatch.Groups["val"].Value

 

jazzc

Elite Member

Jan 27, 2009

2,964

14,717

• Jan 14, 2012

• #7

Code:

ResultString = Regex.Match(SubjectString, "ctoken=(.*?)\\\"").Groups[1].Value;

 

osmose01

Registered Member

Jun 21, 2009

77

5

• Jan 15, 2012

• #8

is the captcha number showing up on the image url , if it really the case it will be really dumb from google and i guess that where you have a problem with your regex.The value might be showing up in your browser but it not really the case.

 

T

tynman

Newbie

Mar 11, 2009

1

0

• Mar 31, 2012

• #9

Look into RegexBuddy. One of the best $30 I ever spent. The time it saves you in learning and debugging regex is amazing!

 

T

theMagicNumber

Regular Member

May 13, 2010

347

197

• Apr 2, 2012

• #10

Code:

  Regex captchaRegex = new Regex("Captcha[?]ctoken=(.+?)\"");
            Match captchaMatch = captchaRegex.Match("<img src=\"example/Captcha?ctoken=Get this\" width=\"200\" height=\"70\" alt=\"Visual verification\">");
            string getThis = captchaMatch.Groups[1].Value;

? is a regex operator, you should escape it with []

 

Satan Claus

Regular Member

Aug 25, 2010

218

193

• Apr 19, 2012

• #11

Try something like this (Second result, haven't tested against yours string)

[\<]img[\ ]src[\=][\"]([^\=]*)[\=]([^\"]*)[\"][\ ]width[\=][\"]([^\"]*)[\"][\ ]height[\=][\"]([^\"]*)[\"][\ ]alt[\=][\"]([^\"]*)[\"][\>]