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Hello everyone,
I have a string array, but may have duplicate strings. Any built-in or smart way to remove the duplicate ones and generate a string array contains only unique ones?
For example, the input array is {"abc", "bcd", "abc"}, the unique output array is {"abc", "bcd"}.
thanks in advance,
George
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from what I know there's no such thing and you'd have to iterate thru and pick the unique ones manually. it's not that difficult you know 
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Thanks Igor,
Good to know .Net does not provide such a class. 
regards,
George
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I dunno why a set class is not included, but it's easy to write one. Just have a list inside, and check if an entry exists before adding it.
Christian Graus
Driven to the arms of OSX by Vista.
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Thanks Christian,
What do you mean "have a list inside"? I am talking about string array, I am not sure where is the list you are talking about. Show some pseudo code?
regards,
George
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public class set<t>
{
private List<t> theList;
public bool Add(T item)
{
if (theList.Contains(item)) return false;
theList.Add(item);
return true;
}
}
This is the start of a set class, a container that only contains one of any object.
Christian Graus
Driven to the arms of OSX by Vista.
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Thanks Christian,
I like your idea. I am surprised why there is no built-in Set class in .Net.
regards,
George
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May be Array.FindAll can help you. Check out MSDN for it.
Another way could be:
1. Create a list/hashtable. Then loop through the array.
2. Check if the element exists in the list/hashtable.
3. If it does its a duplicate value. Remove it from array.
4. If it doesnt add it to the list/hashtable.
C isn't that hard: void (*(*f[])())() defines f as an array of unspecified size, of pointers to functions that return pointers to functions that return void
"Always program as if the person who will be maintaining your program is a violent psychopath that knows where you live." - Martin Golding
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Hi d@nish,
I have studied related MSDN page about Array.FindAll, but I do not think it could help me in my solution. Do you have any pesudo code to show your idea of using Array.FindAll to make a unique string array?
regards,
George
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You have to iteretae it.You can use some generic for that
Cheers!!
Brij
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Hi Brij,
"some generic for that" -- do you have some more words on this? Or some pseudo code?
regards,
George
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List<string> newArray = new List<string>();
foreach (string token in yourArray)
{
if (!newArray.Contains(token))
{
newArray.Add(token);
}
}
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Thanks Igor,
I like your solution! 
regards,
George
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no worries 
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Make a custom function,In which create an a generic as taken below a list.
List<string> UnqueList=new List<string>();
for (int i = 0; i < strarr.Length; i++)
{
if(!UnqueList.Exists(strarr[0]))
{
UnqueList.Add(strarr[0]);
}
}
Now you'll the list conatining unique elements.You can conert it to array too as
UnqueList.ToArray();
Cheers!!
Brij
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Thanks Brij!
The "generic" you mean List<string>?
regards,
George
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Generic does means only List.We have some more like Dictionary,SortedList,Queue,Stack but list suits your requirement best.
Cheers!!
Brij
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Thanks for your clarification, Brij!
regards,
George
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If I'm not mistaken you can use LINQ to select unique values.
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...yes, assuming he's using .net 3+
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Yes, I have to use .Net 3.0, not .Net 3.5. Any ideas for .Net 3.0 based solution? I think LINQ belongs to .Net 3.5, not .Net 3.0?
regards,
George
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LINQ is good, but I have to use .Net 3.0, not .Net 3.5. Any ideas for .Net 3.0 based solution?
regards,
George
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You can use the Distinct method(an Extention Method) if you are using C#3.0 and the implementation code is quit simple, such as:
string[] strs = new string[] { "abc", "bcd", "abc" };
IEnumerable<string> newStrs = strs.Distinct();
Hope this will help.
LuckyBoy
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LuckyBoy,
Distinct belongs to .Net 3.5, and I have to use .Net 3.0.
Any ideas for .Net 3.0?
regards,
George
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George_George wrote: I have to use .Net 3.0
Then I can't suggest HashSet. 
But I can suggest my Set class. 
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