how to compare lists

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.NET

LINQ

Using linq let me know how to compare 2 list of strings.. i oly want to know whether they are equal

Posted 12-Jun-11 22:42pm

Ashakoti

Updated 12-Jun-11 22:48pm

Sergey Alexandrovich Kryukov

v2

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Sergey Alexandrovich Kryukov 13-Jun-11 4:47am

Change a tag Silverlight to .NET, and add LINQ (OK, I did it for you).
Always try to tag accurately, to get better answer sooner.
--SA

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Wayne Gaylard · Answer 1 · 2011-06-12T23:06:00

By equal I expect you mean whether the two lists have the same values, you can use the Except operator and check whether the result has a count of zero (as pointed out by Tarun, you need to check whether both ways are the same ), something like this

C#

List<string> one = new List<string>() { "a", "b", "c" };
           List<string> two = new List<string>() { "a", "b", "c", "d" };
           //If both have same values
           if (one.Except(two).Count() == 0 && two.Except(one).Count() == 0)
           {
               MessageBox.Show("They have same values");
           }
           else
           {
               MessageBox.Show("They are not same.");
           }
           //To ignore case
           if (one.Except(two, StringComparer.CurrentCultureIgnoreCase).Count() == 0 && two.Except(one, StringComparer.CurrentCultureIgnoreCase).Count() == 0)
           {
               MessageBox.Show("They have same values, igoring case");
           }
           else
           {
               MessageBox.Show("They are not same.");
           }
           //If one is same reference as two
           if (one.Equals(two))
           {
               MessageBox.Show("They are the same reference");
           }
           else
           {
               MessageBox.Show("They are not same reference");
           }

Hope this helps

OriginalGriff · Answer 2 · 2011-06-12T23:04:00

Try:

C#

List<string> ListA = new List<string>("hello paul this is a text string".Split(' '));
List<string> ListB = new List<string>("hello paul this is a text string again".Split(' '));
var differences = ListA.Where(x => !ListB.Any(x1 => x1 == x))
.Union(ListB.Where(x => !ListA.Any(x1 => x1 == x)));
if (differences.Count() != 0)
    {
    Console.WriteLine("Different!");
    }

alrosan · Answer 3 · 2011-06-12T23:07:00

Solution 3

static void Main(string[] args)
{
    List<string> List1 = new List<string> { "Car", "Home", "City" };
    List<string> List2 = new List<string> { "Car", "Home", "City" };
    List<string> List3 = new List<string> { "Home", "Car", "City" };
    Console.WriteLine(List1.SequenceEqual(List2));//Result is True
    Console.WriteLine(List1.SequenceEqual(List3));//Result is False

    Console.Read();
}

Posted 12-Jun-11 23:07pm

alrosan

Updated 12-Jun-11 23:09pm

v2

Comments

Wayne Gaylard 13-Jun-11 5:11am

SequenceEqual will only return true if the elements are in exactly the same order. Equals returns true only if both return the same reference.

alrosan 13-Jun-11 5:16am

No try this
List<string> List1 = new List<string> { "Car", "Home", "City" };
List<string> List2 = new List<string> { "Car", "Home", "City","Country" };
Console.WriteLine(List1.SequenceEqual(List2));//Result is False

Wayne Gaylard 13-Jun-11 5:20am

Yes, but the List's have to be both the same number of elements, and the elements have to be in exactly the same order.

alrosan 13-Jun-11 5:24am

give me an example plz

Tarun.K.S 13-Jun-11 5:30am

Although list1 and list3 have the same elements but the order is not correct, the result should be true but in your case, its coming as false which is wrong.

Tarun.K.S 13-Jun-11 5:29am

Hi alrosan, your solution was close too, but it failed when I reordered the elements.

alrosan 13-Jun-11 5:44am

thanks all
static bool IsSameLists(List<string> lst1,List<string> lst2)
{
if (lst1.Count() != lst2.Count())
return false;
for (int c = 0; c < lst1.Count(); c++)
{
if (!(lst1[c] == lst2[c]))
return false;
}
return true;
}

Ashakoti · Answer 4 · 2011-06-12T23:46:00

Solution 4

Hey thanks a lot.. It helped but the thing is that it compares only when count in both the list is same.. No problem,i added one more condition for that..

N please let me know any good source to learn silverlight.. I want to learn in around 45 days.. I can spend 5 hrs per day and more on weekends.. But i want to.. Please do let me know how its possible.. With that i also need to learn Linq in silverlight

Posted 12-Jun-11 23:46pm

Ashakoti

Comments

Tarun.K.S 13-Jun-11 5:54am

Hi, you can learn silverlight from CP articles here : http://www.codeproject.com/KB/silverlight/. Also have a look at these articles by Kunal : http://www.codeproject.com/script/Articles/MemberArticles.aspx?amid=6177366.
Also do vote and accept the answer(s) that helped. Good luck.

how to compare lists

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