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Hi,
I have a pretty big (100'000s of entries) HashMap . Now, I need a HashSet containing all the keys from this HashMap . Unfortunately, HashMap only has a keySet() method which returns a Set but not a HashSet .
What would be an efficient way to generate...
Started by Haes on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
Can you not create the HashSet from an existing Set ? But (more importantly) why are you worried about the implementation returned to you from the keySet() method....
HashSet myHashSet = new HashSet(myHashMap.keySet());
Haven't tried it.
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I have a hashset in C# that Iam removing from if a condition is met while iterating though the hashset and cannot do this using a froeach loop as below.
foreach (String hashVal in hashset) { if (hashVal == "somestring") { hash.Remove("somestring"); } ...
Started by Stuart Burgis on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
This avoids the problem of modifying the hashset whilst....
Any item in the hashset that matches the predicate will be removed.
If(ShouldRemove(index)) Then Remove(index)
Use the RemoveWhere method of HashSet instead to the method.
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How do I convert a HashSet<T> to an array in .NET?
Started by Agnel Kurian on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
Int[] entries = hs.ToArray....
HashSet<int> hs = ...
Using System.Linq; ...
As well use it :
T[] myArray = System.Linq.Enumerable.ToArray(hashSet);
If you mean mean you're on 3.5, just use ToArray since HashSet implements IEnumerable, e.g.
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Ask your Facebook Friends
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What is the equivalent Scala constructor (to create an immutable HashSet ) to the Java:
new HashSet<T>(c)
where c is of type Collection<? extends T> . All I can find in the HashSet Object is apply
Started by oxbow_lakes on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Scala.collection.immutable.HashSet val list = List(1,2,3) val set = HashSet() ++ list.
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I really want to use hashsets in my program. Using a dictionary feels ugly. I'll probably start using VS2008 with .Net 3.5 some day, so my ideal would be that even though I can't (or can I?) use hashsets in VS2005, when I start using .NET 3.5, I don't...
Started by Brian on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
You could use Iesi.Collections (used by NHibernate) or Mono's HashSet
The C5 Library also has a ....
Not really the same thing, but it might simplify things and I'm very pleased with it .
The Dictionary as Hashset with a using directive.
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I need a HashSet that preserves insertion ordering, are there any implementations of this in the framework?
Started by Sam Saffron on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
For sequences that need to persist order, look at List< .
That defeats the purpose of a HashSet.
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I am wondering since the HashSet is implemented via a HashMap instance , what would be the key that would be used to put data into HashSet.
i gone through the link http://www.coderanch.com/t/251832/Programmer-Certification-SCJP/certification/Difference...
Started by sap on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
That way the add , remove.
The key would be the object that went into the hashset itself since keys of maps are sets is to use the object you add to the HashSet as a key of the HashMap .
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According to the HashSet javadoc, HashSet.contains only returns a boolean. How can I "find" an object in a hashSet and modify it (it's not a primitive data type)?
I see that HashTable has a get() method, but I would prefer to use the set.
Answer Snippets (Read the full thread at stackoverflow):
Like:
MyObject obj = new MyObject(); HashSet hashSet = new HashSet(); hashSet.add(obj.
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I am exploring the HashSet<T> type, but I don't understand where it stands in collections.
Can one use it to replace a List<T> ? I imagine the performance of a HashSet<T> to be better, but I couldn't see individual access to its elements...
Started by Joan Venge on
, 10 posts
by 10 people.
Answer Snippets (Read the full thread at stackoverflow):
Instead, what better captures your intent....
Performance would be a bad reason to choose HashSet over List.
A set is a collection of values containing no duplicate is the answer you were looking for .
HashSet is a set implemented by hashing.
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Currently the HashSet<T> constructor that allows you to define your equality comparison yourself is the HashSet<T>(IEqualityComparer<T> comparer) constructor. I would like to define this EqualityComparer as a lambda.
I found this blog...
Started by boris callens on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Class HashSet { public static HashSet<T> Create<T>(Func<T, T, int> func.
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