remove duplicates from array

Question

1.00/5 (1 vote)

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hello,
How to remove duplicates in array using function (not using c# in built function) ..
for example there is an array

string[] str={"1","9","2","7","2","1","9","9"}

i want to remove duplicates from this and form new aaray like

string[] newstr={"1","9","2","7"}

Thanks & Regards
Srishti Gupta

Posted 7-Jul-13 22:44pm

srishti056

Updated 27-May-20 7:22am

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3 solutions

Solution 1

C#

string[] str={"1","9","2","7","2","1","9","9"};
string[] newstr = new HashSet<string>(str).ToArray();</string>

Happy Coding!
:)

Posted 7-Jul-13 22:48pm

Aarti Meswania

Comments

srishti056 8-Jul-13 4:52am

i wanna a function for this not in built function of c#

Solution 2

Quote:
not using c# in built function

Why not? You can simply use the Distinct method instead of writing a method yourself:

C#

string[] newstr = str.Distinct().ToArray();

It's really not necessary to write a method yourself.

[Edit]

If you really want a function that's not built-in, create this extension method:

C#

public static class ExtensionMethods
{
    public static IEnumerable<T> DistinctNonBuiltIn<T>(this IEnumerable<T> source)
    {
        List<T> distinctValues = new List<T>();
        foreach (T val in source)
        {
            if (!distinctValues.Contains(val))
            {
                distinctValues.Add(val);
            }
        }
        return (IEnumerable<T>)distinctValues;
    }
}

And to get the distinct values:

C#

string[] newstr = str.DistinctNonBuiltIn().ToArray();

Hope this helps.

Posted 7-Jul-13 22:48pm

Thomas Daniels

Updated 7-Jul-13 23:18pm

v3

Comments

srishti056 8-Jul-13 4:52am

ya actually its a interview question and he said that write a function itself

Thomas Daniels 8-Jul-13 5:19am

I updated my answer.

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Sushil Mate · Accepted Answer · 2013-07-07T23:13:00

Solution 3

From StackOverFlow.

C#

public string[] RemoveDuplicates(string[] myList) {
       System.Collections.ArrayList newList = new System.Collections.ArrayList();

       foreach (string str in myList)
           if (!newList.Contains(str))
               newList.Add(str);
       return (string[])newList.ToArray(typeof(string));
   }

Posted 7-Jul-13 23:13pm

Sushil Mate

Comments

srishti056 8-Jul-13 5:15am

ok thanks

Sushil Mate 8-Jul-13 5:23am

by the way you should try it by your self first. don't put the question here unless you are stuck somewhere. see next time interviewer will ask another question, it doesn't necessarily they will ask the same question. better to try by yourself. Learn to code not to mug up.