CODEWITHSUNDEEP
.netregex
user73803
user73803

Reputation: 3

.net Regular Expression involving html tags

I'm looking for a regular expression that detects whether or not a string is anything more than a bunch of HTML tags.

So, desired functionality is:

Input -> Output

"<html></html>" -> False

"<html>Hi</html>" -> True

"<a href='google.com'>Click Me</a>" -> True

"hello" -> True

"<bold><italics></bold></italics>" -> False

"" -> Don't care

Once upon a time I could have done this myself, but it's been too long.

Thanks in advance.

edit: I don't care if they are real HTML tags. Lets call anything inside <>'s a tag. Also don't care if a start tag matches up with an end tag.

Upvotes: 0

Views: 1264

Answers (3)

eglasius
eglasius

Reputation: 36035

I once used this to strip out html tags: 

const string tagsPatterns = "\\s*<.*?>\\s*"; 
value = System.Text.RegularExpressions.Regex.Replace(value, tagsPatterns, " ");

I guess you can play with it a bit (this version wanted to keep white spaces), to get the string with no tags, and check if it isn't empty

Update 1: Here it goes :)

bool HasText(string value)
{
    const string tagsPatterns = "<.*?>"; 
    value = System.Text.RegularExpressions.Regex.Replace(value, tagsPatterns, "");
    return value.Trim() != "";
}
[TestMethod]
public void TestMethod2()
{
    Assert.IsFalse(HasText("<html></html>"));
    Assert.IsTrue(HasText("<html>Hi</html>"));
    Assert.IsTrue(HasText("<a href='google.com'>Click Me</a>"));
    Assert.IsTrue(HasText("hello"));
    Assert.IsFalse(HasText("<bold><italics></bold></italics>"));
    Assert.IsFalse(HasText(""));
}

Upvotes: 0

ajma
ajma

Reputation: 12206

Here's an article written by Phil Haack about using a regular express to match html.

Also, if you want a simple line of code, consider loading the string into an XmlDocument. It would parse it so you'll know if you have valid xml or not.

Upvotes: 0

Tomalak
Tomalak

Reputation: 338416

Replace "<[^>]*>" with the empty string, trim the result and check if there is anything left afterwards.

Upvotes: 2

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