Performance of Split vs. Substring and IndexOf?

[Jonas]

Hi!

If I want to get the first element of a delimited string, which of this two
methods would be the best performancevise?

Dim s0 as String = "abc;def;ggg"
Dim s1 as String
Dim s2 as String

Method 1:
s1 = s0.Split(";")(0)

Method 2:
s2 = s0.Substring(0, s0.IndexOf(";"))


Brgds

Jonas

 

[Armin Zingler]

If I want to get the first element of a delimited string, which of
this two methods would be the best performancevise?

Why not test it?

Dim s0 as String = "abc;def;ggg"
Dim s1 as String
Dim s2 as String

Method 1:
s1 = s0.Split(";")(0)

Method 2:
s2 = s0.Substring(0, s0.IndexOf(";"))

I guess Method2 is faster because only the first part is extracted from the
string. You can also try to pass a char instead of a string to IndexOf:

s2 = s0.Substring(0, s0.IndexOf(";"c)) ' ";"c for char literals

 

[Cor]

With this short string?

Dim s0 as String = "abc;def;ggg"

Do you want to know it in 1/10000000000000000000000000 second?

Cor

 

[Cor]

Hi Armin,

I had the same answer but changed it (even with the character).

See my answer.

Cor

 

[Armin Zingler]

Hi Armin,

I had the same answer but changed it (even with the character).

See my answer.

What if it's executed several thousand times in a loop?

 

[Cor]

Hi Armin,

Last week I did a test about this again with the Regex in it, I don't know
if you have seen it.

The processing of the loop did take the most time.

So I think that this kind of things are only a question when it is a long
string, and then it could not be another answer than "just take the 4
characters with the substring" of course.

Cor

 

[Armin Zingler]

Last week I did a test about this again with the Regex in it, I don't
know if you have seen it.

No, I haven't followed the Regex threads.

The processing of the loop did take the most time.

So I think that this kind of things are only a question when it is a
long string, and then it could not be another answer than "just take
the 4 characters with the substring" of course.

You are right, but whenever I have the choice, I choose the faster version.

 

[EricJ]

in addition

are you going to use the other parts of the string?
if so use the split and send it to a string array

eric

 

[Jonas]

It was just an example, the actual string is longer, up to 256 characters.

/Jonas

 

[Cor]

Hi Jonas,

I think you saw my answer with Armin, it is the same as he, but actualy with
strings of 256characters the difference is also almost nothing (on a modern
computer).

But I would choose for your option without the split (when it is not
something Eric said) and then with the small c from character in it as Armin
made in his example.

Cor