How to delete entries from a dictionary using the value

Question

I have a dictionary collection as bleow:

mydic.addvalue(key1, val1)
mydic.addvalue(key2, val1)
mydic.addvalue(key3, val1)
mydic.addvalue(key4, val2)
mydic.ad         


        

Answer 1

You first need to find all keys for which the associated value is val1:

var keysToRemove = mydic.Where(kvp => kvp.Value == val1)
                        .Select(kvp => kvp.Key)
                        .ToArray();

Then you can remove each of those keys:

foreach (var key in keysToRemove)
{
    mydic.Remove(key);
}