Question

I’ve two dictionaries as following:

Dictionary 1:

Dictionary<string, string> dict1 = new Dictionary<string, string>();

request.Add("key1", "value1");

request.Add("key2", "value2");    

request.Add("key3", "value3");

Dictionary 2 :

Dictionary<string, string> request = new Dictionary<string, string>();

request.Add("key1", "value1");

request.Add("key2", "value2");          

I need to compare above two dictionaries using LINQ query with condition:

1) All keys in dict2 should match with keys in dict1

2) The matched keys should have equivalent value

3) Even if the value of key2 in dict2 is empty, it should match

Help on above in appreciated. Thanks in advance.

Regards,

Sachin

Answer 1

You could use the Contains method and provide a custom IEqualityComparer, but an easier way would be to use Any():

var dict1 = new Dictionary<string, string>
{
    {"key1", "value1"},
    {"key2", "value2"},
    {"key3", "value3"}
};

var dict2 = new Dictionary<string, string>
{
    {"key1", "value1"},
    {"key2", "value2"}
};

dict2.All(k2 => 
        dict1.Any(k1 => k1.Key == k2.Key && 
                        (String.IsNullOrEmpty(k2.Value) || k1.Value == k2.Value)))

I guess with empty you mean null or an empty string, hence I used String.IsNullOrEmpty. If you want to just check for null, do a simple k2.Value == null instead.