Regex or wildcard in dictionary.TryGetValue

I have a similar problem like mentioned in this Link, fetching data from Dictionary using partial key and my key DataType is string.

Dictionary

DataType

string

This is how my dictionary looks

Key Values
GUID1+GUID2+GUID3 1, 2, 3
GUID1+GUID2+GUID3 4, 5, 6
GUID1+GUID2+GUID3 7, 8, 9


But the solution provided is fetching data from Dictionary using an extension method with linq in Dictionary. I just want to extract data from Dictionary using TryGetValue passing Regex or wildcard expression.

Dictionary

Dictionary

Dictionary

TryGetValue

Regex

Note that you'll lose any performance gains offered by a dictionary by doing this. The reason is that the dictionary first finds items which match the key's hash code, and then performs equality comparisons on each item key to find the one that is an exact match. If you use any kind of partial/wildcard approach, it's not possible, so you might as well use something like .Where(kv => regex.IsMatch(kv.Key)) to get an IEnumerable with all the matching results.
– john
2 days ago

.Where(kv => regex.IsMatch(kv.Key))

IEnumerable

I'm not sure this is correct but is it possible to create a Dictionary like this Dictionary<Regex, MyClass> myDictionary new Dictionary<Regex, MyClass>() and fetch using regex in myDictionary.TryGetValue("some regex", out myData), will this have any performance impact.
– Leo
2 days ago

Dictionary

Dictionary<Regex, MyClass> myDictionary new Dictionary<Regex, MyClass>()

myDictionary.TryGetValue("some regex", out myData)

Possible duplicate of Is it possible to do a partial string match on a Dictionary string key?
– Sinatr
2 days ago

I referred it, but the solution provided there is using an extension method, but I want to fetch data using TryGetValue method in Dictionary without impacting the performance. This I have mentioned in my question @Sinatr
– Leo
2 days ago

TryGetValue

Dictionary

Sounds like you want a dictionary of dictionaries, where the outer one has GUID+GUID2 as a key and the inner one has GUID3.
– Ry-♦
2 days ago

GUID+GUID2

GUID3

1 Answer
1

A better way of doing this would be to have a dictionary of dictionaries:

Dictionary<Tuple<Guid, Guid>, Dictionary<Guid, string>> dictionary;


And then have extension methods for the sake of simplifying the code where you use it:

public static bool TryGetValue<TKey1, TKey2, TKey3, TValue>(this Dictionary<Tuple<TKey1, TKey2>, Dictionary<TKey3, TValue>> dict, TKey1 key1, TKey2 key2, TKey3 key3, out TValue value)
{
if (dict.TryGetValue(new Tuple<TKey1, TKey2>(key1, key2), out var subDict) && subDict.TryGetValue(key3, out value))
{
return true;
}
value = default(TValue);
return false;
}

public static bool Add<TKey1, TKey2, TKey3, TValue>(this Dictionary<Tuple<TKey1, TKey2>, Dictionary<TKey3, TValue>> dict, TKey1 key1, TKey2 key2, TKey3 key3, TValue value)
{
var mainKey = new Tuple<TKey1, TKey2>(key1, key2);
if (!dict.TryGetValue(mainKey, out var subDict))
{
subDict = new Dictionary<TKey3, TValue>();
dict[mainKey] = subDict;
}
subDict.Add(key3, value);
}


So when you insert into the dictionary, you use the extension method like this:

dictionary.Add(g1, g2, g3, v1);


and then to get a value:

if (dictionary.TryGetValue(g1, g2, g3, out v1))
{

}


Of course, the key of the outer dictionary is up to you. I just used Tuple to illustrate how everything can remain strongly typed.

Tuple

Thanks @john it worked
– Leo
2 days ago

If I solved your problem, please can you accept my answer? Thanks :)
– john
yesterday

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