Extracting data from a string

[rohansakhale]

try using some logic where the angular brackets close & the text starts with out opening angular bracket then u store each char in a character array using pointer.... i can do it in C...didnt start C# yet

[Dman]

I think regex should do the trick

[pankaj]

Yeah, thanks Dman. It helped out.

[Jueki]

It's relatively simple actually. You can use RegEx as mentioned already, here's an example for the "<a tag><c tag>xyz.abc</c></a>" string.

string StringToSearch = "<a tag><c tag>xyz.abc</c></a>";
string StringFound = Regex.Match(StringToSearch, "<a tag><c tag>(.*)<\/c><\/a>").Groups.Item(1).Value;
MessageBox.Show(StringFound);

You can adopt the code yourself for whatever stuff you need
If you need all found matches, use the Matches function instead of Match, then mess around with the Groups and Item array followed by a foreach loop.

[Hyperz]

Never use regex for parsing markup. Download SharpLeech and add a reference to the Engine dll in your project. Then add these using's in your code:

using Hyperz.SharpLeech.Engine.Html;
using Hyperz.SharpLeech.Engine.Net; 

Now you can use it like:

var html = new HtmlDocument();

// load the html
html.LoadHtml("<div class=\"example\">foo</div>");

// use XPath to select the div
var node = html.DocumentNode.SelectSingleNode("//div[@class='example']");
var divContent = HttpUtility.HtmlDecode(node.InnerText); 

XPath info: http://www.w3schools.com/xpath/default.asp

[pankaj]

Where to put this file - Hyperz.SharpLeech.Engine.dll


I guess your code is extracting the word "example" from between //div i.e. <div> tags.
But how to extract links those are starting from http and ends with .extension

[Hyperz]

Can't find what files? You only need Hyperz.SharpLeech.Engine.dll. And nope, the example extracts the word foo. Take a look at XPath via the link I posted.

Regarding the other question:

var html = new HtmlDocument();

// load the html
html.LoadHtml(yourHtmlHere);

// use XPath to select all "A" elements from the html
var anchors = html.DocumentNode.SelectNodes("//a");

// filter out those that start with http
var filter = from a in anchors
             where a.GetAttributeValue("href", "").StartsWith("http")
             select a; 

Just experiment with it.

[Dman]

Never use regex for parsing markup. Download SharpLeech and add a reference to the Engine dll in your project. Then add these using's in your code:

using Hyperz.SharpLeech.Engine.Html;
using Hyperz.SharpLeech.Engine.Net; 

Now you can use it like:

var html = new HtmlDocument();

// load the html
html.LoadHtml("<div class=\"example\">foo</div>");

// use XPath to select the div
var node = html.DocumentNode.SelectSingleNode("//div[@class='example']");
var divContent = HttpUtility.HtmlDecode(node.InnerText); 

XPath info: http://www.w3schools.com/xpath/default.asp

Expand

I beg to differ - regex is much cleaner lol

[Hyperz]

Cleaner? That sounds like something a VB6 coder would say . You being a coder should know that you can't use regex for parsing markup. For one it is much to slow for that. And secondly your expressions are static. It can't handle changes in the DOM structure without having to redo it all. Then there is the issue of inner html, etc etc.

The only case in which you can use regex is when you need only 1 simple string from a small html document of which you know the contents wont change. For anything else it'll change into an slow unmanageable mess. I'd be more happy to put this to the test .

[Dman]

Using a DOM parser is faster than regex? I thought DOM parsers used regex Anyway those parsers use up too much memory. For his case regex is simple - and using a parser is overkill