Can we get key by passing value from dictionary in c# . without loopin

Manoj S

Can we get key by passing value from dictionary in c# . without looping

3 Replies

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Rajanikant Hawaldar5y ago
Accepted answer
Have you used first or default with lambda function? Something like this
dctName.FirstorDefault(i=>I.value==valuepassed).Key
0
Sachin Singh5y ago
please , please explain the scenario where you need key according to value?
keys are unique and value can be duplicate for example
Dictionary dic = new Dictionary();
dic.Add("key1", "Ram");
dic.Add("key2", "Ram");
as you can see the values are same but keys are different , There are mainly 3 types of generic collection
Index based:- List and array list
Key based:- Dictionary and LookUp
priority based:- Stack and Queue

So the purpose of dictionary is to find value based on key,so, in which scenario you want key from value becomes important.
if values are unique
dic.FirstorDefault(x=>x.Value=="myValue").Key ;
if values are duplicate
Dictionary dic = new Dictionary();
           dic.Add("key1", "Ram");
           dic.Add("key2", "Ram");
           var keys = dic.Where(x => x.Value == "myvalue").Select(x => x.Key);
+1
Jignesh Kumar5y ago
Hi Manoj,

Please use this one to get key name by Value in dictionery.
Dictionary<string, string> dic = new Dictionary<string, string>();
dic.Add("1", "one");
dic.Add("2", "two");
dic.Add("3", "three");
dic.Add("4", "four");
dic.Add("5", "five");

string myValues = "five";
var requestedKey = dic.FirstOrDefault(x => x.Value == myValues).Key;
+1