LINQ list of strings in a string

The challenge may not be too clear, but it asks you to see if the 'source' contains any of the strings in the 'stringsToMatch' list. In your code, you're checking to see if the 'stringsToMatch' list contains the 'source' input string, which evaluates to false unless the list contains the exact string in 'source'.

When I enter your code in the code challenge I get the error where it says that "Woohoo!" is passed as the source and "Woo, hoo, oo" is passed as the stringsToMatch list. Since stringsToMatch doesn't contain the string "Woohoo!", your method returns false.

Instead your method should return:

stringsToMatch.Any(word => source.Contains(word));

This code checks to see whether 'source' contains any of the strings in 'stringsToMatch', which is what you want.

FYI, I did solve it the old fashion way, but I'd like to understand how to do it using a LINQ query.

using System.Collections.Generic;

using System.Linq;

namespace Treehouse.CodeChallenges

{

public static class ContainsAnyExtension

{

    public static bool ContainsAny(this string source, IEnumerable<string> stringsToMatch)

    {

        foreach(string word in stringsToMatch)

        {

            if(source.Contains(word))

            {

                return true;

            }

        }

        return false;   

    }

}

}

After a lot of researching, I believe this is the simplest answer that is in accordance with what they were expecting:

using System.Collections.Generic;
using System.Linq;

namespace Treehouse.CodeChallenges
{
    public static class ContainsAnyExtension
    {
        public static bool ContainsAny(this string source, IEnumerable<string> stringsToMatch)
        {
            return stringsToMatch.Any( strings => source.Contains(strings));
        }
    }
}

Essentially the return statement returns a boolean (true / false).

First, the stringsToMatch.Any(...) is looking for anything in it's IEnumerable "List" to return true, and if so, the .Any(...) also returns true to the Return statement -- meaning one of the words passed in by the user was matched with one of our strings.

Second the ** strings => source.Contains(strings) ** is passing in the variable "strings" (which is the parameter data that is an item in the IEnumerable "List"). The function has us check to see if our source parameter contains any of the strings we're checking against. If it's False, it loops to the next item in the IEnumerable "List", else it returns True then it fulfills the Any function, which means, our Contains Any method is returning True also.

I was also struggling with this exercise. This was my solution and it was accepted:

public static bool ContainsAny(this string source, IEnumerable<string> stringsToMatch) { bool result = false; stringsToMatch.ToList().ForEach(s => { if(source.Contains(s)) result = true; }); return result;
}

This also works: return (from s in stringsToMatch where source.Contains(s) select s).Any();