Question

I have a HTML input that have three patterns like this:

Pattern one

</div>

<div class="myclass">

Pattern two

</div>

    <p class="ProductMeta">29-06-2011</p>

<div class="myclass">

Pattern trhee

</div>

    <p class="ProductMeta">29/06/2011</p>

<div class="myclass">

I’m trying to create a RegEx that can catch the tree dates: empty, with dashes and with slashes. I think i need some kind of nested groups, but can’t make it work.

This is the RegEx I’ve created:

Regex r = new Regex(
                @"src=""</div>\s+<p class=""ProductMeta"">([\d\/\-]+)"
                , RegexOptions.Compiled | RegexOptions.IgnoreCase);

And tried the following to make the group optional:

Regex r = new Regex(
                    @"src=""</div>[\s+<p class=""ProductMeta"">([\d\/\-]+)]?"
                    , RegexOptions.Compiled | RegexOptions.IgnoreCase);

Can anyone help me?

The console test does the following to print on screen:

foreach (Match m in mcl)
            {
                Console.WriteLine(m.Groups[1].Value.Replace("-","/") + " - " + m.Groups[5].Value);
            }

            Console.Read();

Thanks.

Answer 1

You can’t make the []‘s an optional group. Only () can be optional.

var test1 = 
@"</div>
<div class=""myclass"">";

var test2 =
@"</div>
    <p class=""ProductMeta"">29-06-2011</p>
<div class=""myclass"">";

var test3 = 
@"</div>
    <p class=""ProductMeta"">29/06/2011</p>
<div class=""myclass"">";

string re = @"</div>\s+(<p class=""ProductMeta"">(\d\d([-/])\d\d\3\d\d\d\d))?";
Regex regExpr = new Regex(re, RegexOptions.Multiline);

Console.WriteLine(regExpr.Match(test1).Groups[2].Value); //== ""
Console.WriteLine(regExpr.Match(test2).Groups[2].Value); //== "29-06-2011" 
Console.WriteLine(regExpr.Match(test3).Groups[2].Value); //== "29/06/2011"