我应该使用 StringBuilder 吗？

Question

I have a code (C# .Net 3.5) that looks like that:

string s1, s2;

for (i=0; i<n; i++)
{
  s1 = "SomeString1"
  s2 = s1 + '.' + i
  SomeList.Add("Bla1" + s2);

  s1 = "SomeString2"
  s2 = s1 + '.' + i
  SomeList("Bla1" + s2);

  s1 = "SomeString3"
  s2 = s1 + '.' + i
  SomeList.Add("Bla1" + s2);
 .
 .
 .
 etc.....
}

for (i=0; i<n; i++)
{
  s1 = "SomeString1"
  s2 = s1 + '.' + i
  SomeList.Add("Bla2" + s2);

  s1 = "SomeString2"
  s2 = s1 + '.' + i
  SomeList("Bla2" + s2);

  s1 = "SomeString3"
  s2 = s1 + '.' + i
  SomeList.Add("Bla2" + s2);
 .
 .
 .
 etc.....
}
.
.
.
etc...

n in not so big (around 5), and this pattern repeats for about 20 times. This happens in the beginning of my program and I want the startup to be faster. The question is: Is there a better way to do that (more efficient)? Should I use string builder instead of creating new strings over and over? Will it help, or the "replace" actions will take as much time?

Thanks, Yossi.

Answer 1

Change:

s1 = "SomeString1"
s2 = s1 + '.' + i
SomeList.Add("Bla2" + s2);

To:

SomeList.Add(string.Format("Bla2SomeString1.{0}", i));

That way you will reduce number of string allocations, concatenations, ...