Is this efficient?

Question

foreach (SessionTeacher sessionTeacher in sessionTeachers)
{
   Person person = EMS.PWDAL.DALHelper.GetPersonByID(sessionTeacher.PersonID);
   ltrlSpeakers.Text += person.Name1 + ", ";
}

here ltrlSpeakers.Text will have something like this "abc, def, " that is extra comma and space at the end which i have to remove.

// removing extra comma and space

ltrlSpeakers.Text = ltrlSpeakers.Text.ToString().Remove(ltrlSpeakers.Text.ToString().Length - 2, 2);

its working fine but is there a better more efficient simple way ?

Is this really one of the least efficient parts of your application? I would be more concerned with the fact that you are using [magic numbers](http://stackoverflow.com/q/47882/299327). — Ryan Gates, Mar 01 '13 at 12:46

score 3 · Accepted Answer · answered Mar 01 '13 at 12:38

3

Something like this:

var personNames = sessionTeachers.Select(
      st => EMS.PWDAL.DALHelper.GetPersonByID(st.PersonID).Name1);
ltrlSpeakers.Text = string.Join(", ", personNames);

answered Mar 01 '13 at 12:38

Andrei

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Stefano Altieri · Answer 2 · 2013-03-01T12:45:47.197

3

Try Using LINQ:

string result = string.Join(",",
(from t in sessionTeachers select EMS.PWDAL.DALHelper.GetPersonByID(t.PersonID).Name1))

edited Mar 01 '13 at 12:45

answered Mar 01 '13 at 12:39

Stefano Altieri

4,473
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I believe the call to ToArray() is not required. – Trevor Tubbs Mar 01 '13 at 12:42
Call to `ToArray` is required for all .NET versions before 4, so this call might be necessary d(http://stackoverflow.com/questions/10092815/why-is-toarray-used-when-using-string-join-with-a-liststring). – Ivan Golović Mar 01 '13 at 13:04

score 1 · Answer 3 · answered Mar 01 '13 at 12:37

1

Use the built-in String.Join method instead.

ltrlSpeakers.Text = string.Join(
    ", ", 
    sessionTeachers.Select(z => z.EMS.PWDAL.DALHelper.GetPersonByID(z.PersonID).Name1);

answered Mar 01 '13 at 12:37

ken2k

46,953
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113
166

score 1 · Answer 4 · answered Mar 01 '13 at 12:40

1

Try it like this:

        ltrlSpeakers.Text = 
        String.Join(", ",
            sessionTeachers
                .Select(teacher => EMS.PWDAL.DALHelper.GetPersonByID(teacher.PersonID).Name1)
                .ToArray()
        );

answered Mar 01 '13 at 12:40

Ivan Golović

8,463
3
24
30

score 0 · Answer 5 · answered Mar 01 '13 at 13:02

best way is ltrlSpeakers.Text = String.Join(", ", sessionTeachers .Select(teacher => EMS.PWDAL.DALHelper.GetPersonByID(teacher.PersonID).Name1) .ToArray() ); ltrlSpeakers.Text = ltrlSpeakers.Text.trimend(',')

Is this efficient?

5 Answers5