Question

I need to count word by LINQ. Here is the code i use to count words in long string array but this not very efficient:

public static int WordCount(string haystack, string needle)
{
    if (needle == null)
    {
        return 0;
    }

    string[] source = haystack.Split(new char[] { '.', '?', '!', ' ', ';', ':', ',', '*', '-' }, StringSplitOptions.RemoveEmptyEntries);
    var matchQuery = from word in source
        where word.ToLowerInvariant() == needle.ToLowerInvariant()
        select word;
    int count=matchQuery.Count();
    return count;
}

Suppose i have a string like this:

Geo Prism GEO 1995 GEO* - ABS #16213899 HGEO-

If i try to find GEO in the above sentence, my routine doesn’t return the right count: I’d expect 4.
What’s wrong with my routine ?

Answer 1

You can have it as one-liner with LINQ:

void Main()
{
    string data = "Geo Prism GEO 1995 GEO* - ABS #16213899 HGEO-";
    var target = "GEO";
    var count = data.Select((c, i) => data.Substring(i)).Count(sub => sub.ToUpper().StartsWith(target));
    Console.WriteLine(count.ToString());
}

---

Result:

4