Count from html string without using HtmlDoc

Question

I want to count the number of rows in html string returned from API. Any idea to get the rows count without using html agility pack ?

following code will connect to API and return html string for apiContent.

using (var client = new HttpClient())
{
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    var response = client.GetAsync(apiURL).Result;
    using (HttpContent content = response.Content)
    {
        Task<string> result = content.ReadAsStringAsync();
        apiContent = result.Result;
    }
}

now i need to count the numbers of row (tr) from html string in variable "apiContent" but without using html agility pack.

What if there are nested rows? You want to count them to or only the top level? — Magnetron, Sep 02 '19 at 15:50
@andyb952 Are you suggesting to parse some HTML with a Regex? — aloisdg, Sep 02 '19 at 15:54
@andyb952 https://stackoverflow.com/questions/590747/using-regular-expressions-to-parse-html-why-not also: https://stackoverflow.com/a/1732454/1248177 — aloisdg, Sep 02 '19 at 16:08
thanks. never think about regex just now. now i get the rowcount with just one row of code : Regex.Matches(apiContent, @".*<\/tr>").Count. :) — Yanly, Sep 02 '19 at 16:08
@Yanly be careful with regex. Take the time to read both links above. — aloisdg, Sep 02 '19 at 16:08

score 1 · Answer 1 · answered Sep 02 '19 at 15:51

1

If the only <TR>'s being returned are what you are interested in, why not just do a LINQ .Count()?

int count = result.Count(f => f == '<tr');

answered Sep 02 '19 at 15:51

Patrick

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What if you have some commented ` – aloisdg Sep 02 '19 at 15:55
If the commenting follows a standard format, just do `f => f == ' – Patrick Sep 02 '19 at 16:11
2

what if your html includes something like `` – BurnsBA Sep 02 '19 at 17:10

aloisdg · Answer 2 · 2019-09-02T16:41:35.447

Here is a robust solution without HtmlAgilityPack.

Lets consider this HTML:

var html = "<table><tr><td>cell</td></tr><!--<tr><td>comment</td></tr>--></table>"

Lets load this HTML as a document:

// Create a new context for evaluating webpages with the default configuration
var context = BrowsingContext.New(Configuration.Default);
// Parse the document from the content of a response to a virtual request
var document = await context.OpenAsync(req => req.Content(html));

Query whatever you are looking for in your HTML:

var rows = document.QuerySelectorAll("tr");
Console.WriteLine(rows.Count());

Try it online!

Whenever you want to parse HTML, always rely on a HTML parser. If you dont want to use HAP, AngleSharp is a great alternative. If you dont want to use an existing HTML parser, you are doomed to make your own. It will be easier on a subset of HTML, but mostly not worth the hassle. Help yourself ; use a library.

Count from html string without using HtmlDoc

2 Answers2