Question

I am trying to grab all the items in the dictionary based on given string which matches partially or fully.

I tried the following code but doesn’t seems to work

a.Where(d => d.Value.Contains(text)).ToDictionary(d => d.Key, d => d.Value);

Can you please tell me how to achieve this ?

Answer 1

The code you’ve given should work absolutely fine, assuming you really wanted to find entries where the value had a partial match. If you’re seeing something else, I suspect your diagnostics are flawed. If you wanted to find entries where the key had a partial match, you just want to swap

a.Where(d => d.Value.Contains(text))

for

a.Where(d => d.Key.Contains(text))

Short but complete program demonstrating the code you’ve given working:

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

class Test
{
    static void Main()
    {
        var original = new Dictionary<string, string> {
            { "a", "foo" },
            { "b", "bar" },
            { "c", "good" },
            { "d", "bad" },
        };

        string needle = "oo";

        var filtered = original.Where(d => d.Value.Contains(needle))
                               .ToDictionary(d => d.Key, d => d.Value);

        foreach (var pair in filtered)
        {
            Console.WriteLine("{0} => {1}", pair.Key, pair.Value);
        }
    }
}

Output:

a => foo
c => good