What's better then somestring=""

[**Developer**]

I understand that

If somestring.leng th = 0 Then

is faster then

If somestring = "" Then

and is equivalent to

If (somestring is Nothing) AndAlso (somestring = "") Then

Is that correct???

Also is there something better then:

somestring = ""

Thanks

[Ken Tucker [MVP]]

Hi,

There is string.empty
http://msdn.microsoft.com/library/de...emptytopic.asp

Ken
-----------------
" **Developer**" <RE************ *@a-znet.com> wrote in message
news:OE******** ******@tk2msftn gp13.phx.gbl...

I understand that

If somestring.leng th = 0 Then

is faster then

If somestring = "" Then

and is equivalent to

If (somestring is Nothing) AndAlso (somestring = "") Then

Is that correct???

Also is there something better then:

somestring = ""

Thanks

[Scott M.]

somestring = string.empty should be faster than using "", since anytime you
use double quotes, new string object is created in memory, but when you use
string.empty, you are comparing against a known constant.
" **Developer**" <RE************ *@a-znet.com> wrote in message
news:OE******** ******@tk2msftn gp13.phx.gbl...

I understand that

If somestring.leng th = 0 Then

is faster then

If somestring = "" Then

and is equivalent to

If (somestring is Nothing) AndAlso (somestring = "") Then

Is that correct???

Also is there something better then:

somestring = ""

Thanks

[Mattias Sjögren]

somestring = string.empty should be faster than using "", since anytime you
use double quotes, new string object is created in memory, but when you use
string.empty , you are comparing against a known constant.

No, you'll get the same empty string object in both cases. Try this

Dim s1 As String = ""
Dim s2 As String = ""
Console.WriteLi ne(s1 Is s2)
Console.WriteLi ne(s1 Is String.Empty)
Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/ | http://www.dotnetinterop.com
Please reply only to the newsgroup.

[Cor Ligthert [MVP]]

Developer,

In my idea is better not to think about performances got by this, it will
probably be something as 0,0000001 nanosecond and in the future even less.

You can in your live never win the time, that you did spent thinking about
it.

Just my idea

Cor

[Herfried K. Wagner [MVP]]

"Ken Tucker [MVP]" <vb***@bellsout h.net> schrieb:

There is string.empty
http://msdn.microsoft.com/library/de...emptytopic.asp

Yeah, but 'String.Empty' is the same as "" (a zero-length string). In terms
of readability I perfer "" over 'String.Empty'.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Herfried K. Wagner [MVP]]

"Mattias Sjögren" <ma************ ********@mvps.o rg> schrieb:

somestring = string.empty should be faster than using "", since anytime
you
use double quotes, new string object is created in memory, but when you
use
string.empt y, you are comparing against a known constant.

No, you'll get the same empty string object in both cases. Try this

Dim s1 As String = ""
Dim s2 As String = ""
Console.WriteLi ne(s1 Is s2)
Console.WriteLi ne(s1 Is String.Empty)

That's true. The empty string is interned, and thus not duplicated:

\\\
MsgBox(String.I sInterned("") Is Nothing) ' False.
///

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Cor Ligthert [MVP]]

Herfried,

Yeah, but 'String.Empty' is the same as "" (a zero-length string). In
terms of readability I perfer "" over 'String.Empty'.

I prefer it because of typing

:-))

Cor

[Herfried K. Wagner [MVP]]

"Cor Ligthert [MVP]" <no************ @planet.nl> schrieb:

Yeah, but 'String.Empty' is the same as "" (a zero-length string). In
terms of readability I perfer "" over 'String.Empty'.

I prefer it because of typing

:-))

That's a valid reason too ;-).

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Herfried K. Wagner [MVP]]

" **Developer**" <RE************ *@a-znet.com> schrieb:

I understand that

If somestring.leng th = 0 Then

is faster then

If somestring = "" Then
There is a big difference between the two approaches. The first one will
crash with a 'NullReferenceE xception' if 'somestring' contains a
null-reference. The latter approach won't crash, it will simply return
'False' for the expression 'somestring = ""' because a reference to '""' is
not the same as a reference to 'Nothing'.
and is equivalent to

If (somestring is Nothing) AndAlso (somestring = "") Then

Is that correct???

No, that's not correct.

Personally I prefer to use the 'Len' function because it will return 0 as
length even for null-references:

\\\
Dim s As String = Nothing
MsgBox(Len(s)) ' 0.
s = ""
MsgBox(Len(s)) ' 0.
///

If you want an exception to be thrown for a null-reference, use the 'String'
object's 'Length' property.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>