StringBuilder

[Alvin Bruney]

Is string builder intelligent enough to handle concats without behaving like
string?

Consider
myStringBuilder .Append("one" + "two")

what does the '+' do here? Because this syntax is also legal but what is the
cost compared to
myStringBuilder .Append("one");
myStringBuilder .Append("two");

and is there a Microsoft recommended pattern for this?

[Greg Ewing [MVP]]

Re: StringBuilder

Alvin, your first example, myStringBuilder .Append("one" + "two") will
basically compile to a string concatenation and then the stringbuilder
append.

Overall doing an Append twice will be faster. If you are only doing it once
though it's not a huge difference.

--
Greg Ewing [MVP]

http://www.citidc.com

"Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote in
message news:uKmSUZhfDH A.3076@tk2msftn gp13.phx.gbl...[color=blue]
> Is string builder intelligent enough to handle concats without behaving[/color]
like[color=blue]
> string?
>
> Consider
> myStringBuilder .Append("one" + "two")
>
> what does the '+' do here? Because this syntax is also legal but what is[/color]
the[color=blue]
> cost compared to
> myStringBuilder .Append("one");
> myStringBuilder .Append("two");
>
> and is there a Microsoft recommended pattern for this?
>
>[/color]

[Kieran Benton]

Re: StringBuilder

I'm sure Jon Skeet took a look at the IL for this kind of thing a while ago
and noted the C# compiler is smart enought to make the "one" and "two"
constants "onetwo" at compile time. Of course this wont work if your soing
something at runtime.

HTH
Kieran

"Greg Ewing [MVP]" <gewing@_NO_SPA M_gewing.com> wrote in message
news:uv0LIlhfDH A.2984@TK2MSFTN GP11.phx.gbl...[color=blue]
> Alvin, your first example, myStringBuilder .Append("one" + "two") will
> basically compile to a string concatenation and then the stringbuilder
> append.
>
> Overall doing an Append twice will be faster. If you are only doing it[/color]
once[color=blue]
> though it's not a huge difference.
>
> --
> Greg Ewing [MVP]
> http://www.citidc.com
>
>
> "Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote in
> message news:uKmSUZhfDH A.3076@tk2msftn gp13.phx.gbl...[color=green]
> > Is string builder intelligent enough to handle concats without behaving[/color]
> like[color=green]
> > string?
> >
> > Consider
> > myStringBuilder .Append("one" + "two")
> >
> > what does the '+' do here? Because this syntax is also legal but what is[/color]
> the[color=green]
> > cost compared to
> > myStringBuilder .Append("one");
> > myStringBuilder .Append("two");
> >
> > and is there a Microsoft recommended pattern for this?
> >
> >[/color]
>
>[/color]

[Jon Skeet]

Re: StringBuilder

Kieran Benton <kieran@teejpc. homeip.net> wrote:[color=blue]
> I'm sure Jon Skeet took a look at the IL for this kind of thing a while ago
> and noted the C# compiler is smart enought to make the "one" and "two"
> constants "onetwo" at compile time. Of course this wont work if your soing
> something at runtime.[/color]

Indeed - and it's even specified in the C# specification, section
14.15, which governs what counts as a constant expression and then
states:

<quote>
Whenever an expression is of one of the types listed above and contains
only the constructs listed above, the expression is evaluated at
compile-time.
</quote>


--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[TJoker .NET [MVP]]

Re: StringBuilder

My two cents.
For a smal number of string operations, the StringBuilder may even be slower
than regular string concatenation. I don't know of any rule of thumb when
deciding which approach to use, but usually I resort to a StringBuilder when
I see concatenations inside a for/while loop or if massive text replacement
is being done in a long text.


--
TJoker, MCSD.NET
MVP: Paint, Notepad, Solitaire

*************** *************** **********


"Greg Ewing [MVP]" <gewing@_NO_SPA M_gewing.com> wrote in message
news:uv0LIlhfDH A.2984@TK2MSFTN GP11.phx.gbl...[color=blue]
> Alvin, your first example, myStringBuilder .Append("one" + "two") will
> basically compile to a string concatenation and then the stringbuilder
> append.
>
> Overall doing an Append twice will be faster. If you are only doing it[/color]
once[color=blue]
> though it's not a huge difference.
>
> --
> Greg Ewing [MVP]
> http://www.citidc.com
>
>
> "Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote in
> message news:uKmSUZhfDH A.3076@tk2msftn gp13.phx.gbl...[color=green]
> > Is string builder intelligent enough to handle concats without behaving[/color]
> like[color=green]
> > string?
> >
> > Consider
> > myStringBuilder .Append("one" + "two")
> >
> > what does the '+' do here? Because this syntax is also legal but what is[/color]
> the[color=green]
> > cost compared to
> > myStringBuilder .Append("one");
> > myStringBuilder .Append("two");
> >
> > and is there a Microsoft recommended pattern for this?
> >
> >[/color]
>
>[/color]

[Alvin Bruney]

Re: StringBuilder

well for starters, i got this kind of construct peppered all over my code. i
start off with good intentions with the append but there seems to always be
a piece of string needing to be added and not worth the starting a new line.
i know that is so lazy. always figured the language was smart enough to know
better.

i didn't care to read spec 14.15. what does it say in the queens english? do
i need to stop doing that (is really what i am asking)

"TJoker .NET [MVP]" <nospam@nonono. no> wrote in message
news:#nO12$ifDH A.3616@TK2MSFTN GP11.phx.gbl...[color=blue]
> My two cents.
> For a smal number of string operations, the StringBuilder may even be[/color]
slower[color=blue]
> than regular string concatenation. I don't know of any rule of thumb when
> deciding which approach to use, but usually I resort to a StringBuilder[/color]
when[color=blue]
> I see concatenations inside a for/while loop or if massive text[/color]
replacement[color=blue]
> is being done in a long text.
>
>
> --
> TJoker, MCSD.NET
> MVP: Paint, Notepad, Solitaire
>
> *************** *************** **********
>
>
> "Greg Ewing [MVP]" <gewing@_NO_SPA M_gewing.com> wrote in message
> news:uv0LIlhfDH A.2984@TK2MSFTN GP11.phx.gbl...[color=green]
> > Alvin, your first example, myStringBuilder .Append("one" + "two") will
> > basically compile to a string concatenation and then the stringbuilder
> > append.
> >
> > Overall doing an Append twice will be faster. If you are only doing it[/color]
> once[color=green]
> > though it's not a huge difference.
> >
> > --
> > Greg Ewing [MVP]
> > http://www.citidc.com
> >
> >
> > "Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote[/color][/color]
in[color=blue][color=green]
> > message news:uKmSUZhfDH A.3076@tk2msftn gp13.phx.gbl...[color=darkred]
> > > Is string builder intelligent enough to handle concats without[/color][/color][/color]
behaving[color=blue][color=green]
> > like[color=darkred]
> > > string?
> > >
> > > Consider
> > > myStringBuilder .Append("one" + "two")
> > >
> > > what does the '+' do here? Because this syntax is also legal but what[/color][/color][/color]
is[color=blue][color=green]
> > the[color=darkred]
> > > cost compared to
> > > myStringBuilder .Append("one");
> > > myStringBuilder .Append("two");
> > >
> > > and is there a Microsoft recommended pattern for this?
> > >
> > >[/color]
> >
> >[/color]
>
>[/color]

[Michael Mayer]

Re: StringBuilder

But be sure to think code readability, as well. For example, this is a lot
more readable:

string name = lastname + ", " + firstname;

then the following

StringBuilder nameBuilder = new StringBuilder() ;
nameBuilder.App end (lastname);
nameBuilder.App end (", ");
nameBuilder.App end (firstname);
string name = nameBuilder.ToS tring();

Not to mention that the first is quicker to write and less error prone, and
quite possibly faster in execution.

I would even suggest that if you're concatenating 100,000 names, still only
use the string builder to put all the names together, something like:

StringBuilder nameBuilder = new StringBuilder() ;
foreach (DataRow row in myDataTable)
{
nameBuilder.App end (row[lastname] + ", " + row[firstname] +
Environment.New Line);
}

instead of:

StringBuilder nameBuilder = new StringBuilder() ;
foreach (DataRow row in myDataTable)
{
nameBuilder.App end (row[lastname]);
nameBuilder.App end (", ");
nameBuilder.App end (row[firstname]);
nameBuilder.App end (Environment.Ne wLine);
}


I think this simplistic case would be fairly readable written either way,
but the first example keeps the name grouped together nicely, so if you add
an address, and other stuff, you don't need to split it all out with
comments:

//Add name
four
lines
to build
name

// Add Address
eight
lines of
code to
assemble
an address
from street, city state, etc

and on.

--
Mike Mayer

http://www.mag37.com/csharp/

mike@mag37.com


"Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote in
message news:O88v%23Wlf DHA.2152@tk2msf tngp13.phx.gbl. ..[color=blue]
> well for starters, i got this kind of construct peppered all over my code.[/color]
i[color=blue]
> start off with good intentions with the append but there seems to always[/color]
be[color=blue]
> a piece of string needing to be added and not worth the starting a new[/color]
line.[color=blue]
> i know that is so lazy. always figured the language was smart enough to[/color]
know[color=blue]
> better.
>
> i didn't care to read spec 14.15. what does it say in the queens english?[/color]
do[color=blue]
> i need to stop doing that (is really what i am asking)
>
> "TJoker .NET [MVP]" <nospam@nonono. no> wrote in message
> news:#nO12$ifDH A.3616@TK2MSFTN GP11.phx.gbl...[color=green]
> > My two cents.
> > For a smal number of string operations, the StringBuilder may even be[/color]
> slower[color=green]
> > than regular string concatenation. I don't know of any rule of thumb[/color][/color]
when[color=blue][color=green]
> > deciding which approach to use, but usually I resort to a StringBuilder[/color]
> when[color=green]
> > I see concatenations inside a for/while loop or if massive text[/color]
> replacement[color=green]
> > is being done in a long text.
> >
> >
> > --
> > TJoker, MCSD.NET
> > MVP: Paint, Notepad, Solitaire
> >
> > *************** *************** **********
> >
> >
> > "Greg Ewing [MVP]" <gewing@_NO_SPA M_gewing.com> wrote in message
> > news:uv0LIlhfDH A.2984@TK2MSFTN GP11.phx.gbl...[color=darkred]
> > > Alvin, your first example, myStringBuilder .Append("one" + "two") will
> > > basically compile to a string concatenation and then the stringbuilder
> > > append.
> > >
> > > Overall doing an Append twice will be faster. If you are only doing[/color][/color][/color]
it[color=blue][color=green]
> > once[color=darkred]
> > > though it's not a huge difference.
> > >
> > > --
> > > Greg Ewing [MVP]
> > > http://www.citidc.com
> > >
> > >
> > > "Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote[/color][/color]
> in[color=green][color=darkred]
> > > message news:uKmSUZhfDH A.3076@tk2msftn gp13.phx.gbl...
> > > > Is string builder intelligent enough to handle concats without[/color][/color]
> behaving[color=green][color=darkred]
> > > like
> > > > string?
> > > >
> > > > Consider
> > > > myStringBuilder .Append("one" + "two")
> > > >
> > > > what does the '+' do here? Because this syntax is also legal but[/color][/color][/color]
what[color=blue]
> is[color=green][color=darkred]
> > > the
> > > > cost compared to
> > > > myStringBuilder .Append("one");
> > > > myStringBuilder .Append("two");
> > > >
> > > > and is there a Microsoft recommended pattern for this?
> > > >
> > > >
> > >
> > >[/color]
> >
> >[/color]
>
>[/color]

[Jay B. Harlow [MVP - Outlook]]

Re: StringBuilder

Michael,
Just remember though that:[color=blue]
> StringBuilder nameBuilder = new StringBuilder() ;
> foreach (DataRow row in myDataTable)
> {
> nameBuilder.App end (row[lastname] + ", " + row[firstname] +
> Environment.New Line);
> }[/color]
For a 100,000 names you just created 100,000 string objects that will need
to be garbage collected.

Where as:[color=blue]
> StringBuilder nameBuilder = new StringBuilder() ;
> foreach (DataRow row in myDataTable)
> {
> nameBuilder.App end (row[lastname]);
> nameBuilder.App end (", ");
> nameBuilder.App end (row[firstname]);
> nameBuilder.App end (Environment.Ne wLine);
> }
>[/color]
Will not create 100,000 string objects.

In both cases you should set the initial capacity on the StringBuilder
constructor as the internal buffer is going to be reallocated each time it
runs out of space. The buffer starts at 16 if nothing no value is given.
Normally you need to make an guess an approximate how much capacity you will
need, for example 100,000 names * (25 first name + 25 last name + 1 comma +
1 newline) = 5,200,000.

I normally avoid calling String.Concat (C# + or VB.NET & on strings) when
using a StringBuilder as part of the reason I use the StringBuilder is to
avoid any intermediate string objects on heap. Using String.Concat with
StringBuilder is just creating those objects...

Just a thought
Jay

"Michael Mayer" <mike@mag37.com > wrote in message
news:%23ufPCImf DHA.1732@TK2MSF TNGP12.phx.gbl. ..[color=blue]
> But be sure to think code readability, as well. For example, this is a[/color]
lot[color=blue]
> more readable:
>
> string name = lastname + ", " + firstname;
>
> then the following
>
> StringBuilder nameBuilder = new StringBuilder() ;
> nameBuilder.App end (lastname);
> nameBuilder.App end (", ");
> nameBuilder.App end (firstname);
> string name = nameBuilder.ToS tring();
>
> Not to mention that the first is quicker to write and less error prone,[/color]
and[color=blue]
> quite possibly faster in execution.
>
> I would even suggest that if you're concatenating 100,000 names, still[/color]
only[color=blue]
> use the string builder to put all the names together, something like:
>
> StringBuilder nameBuilder = new StringBuilder() ;
> foreach (DataRow row in myDataTable)
> {
> nameBuilder.App end (row[lastname] + ", " + row[firstname] +
> Environment.New Line);
> }
>
> instead of:
>
> StringBuilder nameBuilder = new StringBuilder() ;
> foreach (DataRow row in myDataTable)
> {
> nameBuilder.App end (row[lastname]);
> nameBuilder.App end (", ");
> nameBuilder.App end (row[firstname]);
> nameBuilder.App end (Environment.Ne wLine);
> }
>
>
> I think this simplistic case would be fairly readable written either way,
> but the first example keeps the name grouped together nicely, so if you[/color]
add[color=blue]
> an address, and other stuff, you don't need to split it all out with
> comments:
>
> //Add name
> four
> lines
> to build
> name
>
> // Add Address
> eight
> lines of
> code to
> assemble
> an address
> from street, city state, etc
>
> and on.
>
> --
> Mike Mayer
> http://www.mag37.com/csharp/
> mike@mag37.com
>
>
> "Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote in
> message news:O88v%23Wlf DHA.2152@tk2msf tngp13.phx.gbl. ..[color=green]
> > well for starters, i got this kind of construct peppered all over my[/color][/color]
code.[color=blue]
> i[color=green]
> > start off with good intentions with the append but there seems to always[/color]
> be[color=green]
> > a piece of string needing to be added and not worth the starting a new[/color]
> line.[color=green]
> > i know that is so lazy. always figured the language was smart enough to[/color]
> know[color=green]
> > better.
> >
> > i didn't care to read spec 14.15. what does it say in the queens[/color][/color]
english?[color=blue]
> do[color=green]
> > i need to stop doing that (is really what i am asking)
> >
> > "TJoker .NET [MVP]" <nospam@nonono. no> wrote in message
> > news:#nO12$ifDH A.3616@TK2MSFTN GP11.phx.gbl...[color=darkred]
> > > My two cents.
> > > For a smal number of string operations, the StringBuilder may even be[/color]
> > slower[color=darkred]
> > > than regular string concatenation. I don't know of any rule of thumb[/color][/color]
> when[color=green][color=darkred]
> > > deciding which approach to use, but usually I resort to a[/color][/color][/color]
StringBuilder[color=blue][color=green]
> > when[color=darkred]
> > > I see concatenations inside a for/while loop or if massive text[/color]
> > replacement[color=darkred]
> > > is being done in a long text.
> > >
> > >
> > > --
> > > TJoker, MCSD.NET
> > > MVP: Paint, Notepad, Solitaire
> > >
> > > *************** *************** **********
> > >
> > >
> > > "Greg Ewing [MVP]" <gewing@_NO_SPA M_gewing.com> wrote in message
> > > news:uv0LIlhfDH A.2984@TK2MSFTN GP11.phx.gbl...
> > > > Alvin, your first example, myStringBuilder .Append("one" + "two")[/color][/color][/color]
will[color=blue][color=green][color=darkred]
> > > > basically compile to a string concatenation and then the[/color][/color][/color]
stringbuilder[color=blue][color=green][color=darkred]
> > > > append.
> > > >
> > > > Overall doing an Append twice will be faster. If you are only doing[/color][/color]
> it[color=green][color=darkred]
> > > once
> > > > though it's not a huge difference.
> > > >
> > > > --
> > > > Greg Ewing [MVP]
> > > > http://www.citidc.com
> > > >
> > > >
> > > > "Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com>[/color][/color][/color]
wrote[color=blue][color=green]
> > in[color=darkred]
> > > > message news:uKmSUZhfDH A.3076@tk2msftn gp13.phx.gbl...
> > > > > Is string builder intelligent enough to handle concats without[/color]
> > behaving[color=darkred]
> > > > like
> > > > > string?
> > > > >
> > > > > Consider
> > > > > myStringBuilder .Append("one" + "two")
> > > > >
> > > > > what does the '+' do here? Because this syntax is also legal but[/color][/color]
> what[color=green]
> > is[color=darkred]
> > > > the
> > > > > cost compared to
> > > > > myStringBuilder .Append("one");
> > > > > myStringBuilder .Append("two");
> > > > >
> > > > > and is there a Microsoft recommended pattern for this?
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >[/color]
> >
> >[/color]
>
>[/color]

[Michael Mayer]

Re: StringBuilder

"Jay B. Harlow [MVP - Outlook]" <Jay_Harlow@ema il.msn.com> wrote in message
news:%2367W8Zmf DHA.3284@tk2msf tngp13.phx.gbl. ..[color=blue]
> Michael,
> Just remember though that:[color=green]
> > StringBuilder nameBuilder = new StringBuilder() ;
> > foreach (DataRow row in myDataTable)
> > {
> > nameBuilder.App end (row[lastname] + ", " + row[firstname] +
> > Environment.New Line);
> > }[/color]
> For a 100,000 names you just created 100,000 string objects that will need
> to be garbage collected.[/color]

Ok, I agree (and I guess it's worse since there's three concats in the above
so it would probably result in 300,000 temporary strings). I haven't really
ever tried to do the above for such a big number of strings - I might make
an example to see how bad it is. Most of the data I've used would only try
to concat a few dozens of records at a time, where you can get by with
runtime ineffeciencies.

The main thing I try to avoid is copying of the entire string over and over
(as you'd get if you did text += newStuff a whole bunch of times). But there
certainly are advantages to avoiding the short strings when there will be a
lot of them.
[color=blue]
> I normally avoid calling String.Concat (C# + or VB.NET & on strings) when
> using a StringBuilder as part of the reason I use the StringBuilder is to
> avoid any intermediate string objects on heap. Using String.Concat with
> StringBuilder is just creating those objects...[/color]

I guess I would have to agree, in retrospect, since a few hundred thousand
extra strings on the heap isn't optimal - when they can easily be avoided
altogether.


--
Mike Mayer

http://www.mag37.com/csharp/

mike@mag37.com

[Jon Skeet]

Re: StringBuilder

Alvin Bruney <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote:[color=blue]
> well for starters, i got this kind of construct peppered all over my code. i
> start off with good intentions with the append but there seems to always be
> a piece of string needing to be added and not worth the starting a new line.
> i know that is so lazy. always figured the language was smart enough to know
> better.[/color]

Not sure exactly which construct you mean here, to be honest.
[color=blue]
> i didn't care to read spec 14.15. what does it say in the queens english? do
> i need to stop doing that (is really what i am asking)[/color]

It says that "literal1"+"lit eral2" is always evaluated at compile-time
to "literal1litera l2".

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Jon Skeet]

Re: StringBuilder

Michael Mayer <mike@mag37.com > wrote:[color=blue]
> Ok, I agree (and I guess it's worse since there's three concats in the above
> so it would probably result in 300,000 temporary strings).[/color]

Nope, there's only 100,000, actually, although there are also 100,000
string arrays created briefly. The line of:

String x = a + ',' + b + 'x';

is compiled to String.Concat (new object[] {a, ',', b, 'x'});

--
Jon Skeet - <skeet@pobox.co m>

http://www.pobox.com/~skeet

If replying to the group, please do not mail me too

[Jay B. Harlow [MVP - Outlook]]

Re: StringBuilder

Michael,[color=blue]
> Ok, I agree (and I guess it's worse since there's three concats in the[/color]
above[color=blue]
> so it would probably result in 300,000 temporary strings). I haven't[/color]
really
As Jon said there are only 100,000 temporary strings. Then 100,000 temporary
string arrays.

Interesting: String.Concat is overloaded for variable number of strings & a
variable number of objects. When overloading for a variable number of
parameters (params) its common to have overloads for a fixed number such as
1, 2 and 3, as it avoids the temporary array to hold the parameters in these
cases.

String.Concat can concatenate up to 4 strings before it needs to use the
params version and create the array. However can only concatenate up to 3
objects before it needs to use the params version. Interesting I would
expect both to been 3 or both 4. Hmm...

Hope this helps
Jay

"Michael Mayer" <mike@mag37.com > wrote in message
news:elMzwumfDH A.1212@TK2MSFTN GP12.phx.gbl...[color=blue]
> "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow@ema il.msn.com> wrote in[/color]
message[color=blue]
> news:%2367W8Zmf DHA.3284@tk2msf tngp13.phx.gbl. ..[color=green]
> > Michael,
> > Just remember though that:[color=darkred]
> > > StringBuilder nameBuilder = new StringBuilder() ;
> > > foreach (DataRow row in myDataTable)
> > > {
> > > nameBuilder.App end (row[lastname] + ", " + row[firstname] +
> > > Environment.New Line);
> > > }[/color]
> > For a 100,000 names you just created 100,000 string objects that will[/color][/color]
need[color=blue][color=green]
> > to be garbage collected.[/color]
>
> Ok, I agree (and I guess it's worse since there's three concats in the[/color]
above[color=blue]
> so it would probably result in 300,000 temporary strings). I haven't[/color]
really[color=blue]
> ever tried to do the above for such a big number of strings - I might make
> an example to see how bad it is. Most of the data I've used would only try
> to concat a few dozens of records at a time, where you can get by with
> runtime ineffeciencies.
>
> The main thing I try to avoid is copying of the entire string over and[/color]
over[color=blue]
> (as you'd get if you did text += newStuff a whole bunch of times). But[/color]
there[color=blue]
> certainly are advantages to avoiding the short strings when there will be[/color]
a[color=blue]
> lot of them.
>[color=green]
> > I normally avoid calling String.Concat (C# + or VB.NET & on strings)[/color][/color]
when[color=blue][color=green]
> > using a StringBuilder as part of the reason I use the StringBuilder is[/color][/color]
to[color=blue][color=green]
> > avoid any intermediate string objects on heap. Using String.Concat with
> > StringBuilder is just creating those objects...[/color]
>
> I guess I would have to agree, in retrospect, since a few hundred thousand
> extra strings on the heap isn't optimal - when they can easily be avoided
> altogether.
>
>
> --
> Mike Mayer
> http://www.mag37.com/csharp/
> mike@mag37.com
>
>
>[/color]

[Alvin Bruney]

Re: StringBuilder

> Not sure exactly which construct you mean here, to be honest.
was talking about .append(blah + moreblah) as opposed to .append(blah);
..append(morebl ah)
[color=blue]
> It says that "literal1"+"lit eral2" is always evaluated at compile-time
> to "literal1litera l2".[/color]

ok well that seems to be good for me then since it evaluates it at compile
time. but what happens at run-time? what if literal2 was a string object
(not interned) - as would frequently be the case. does it know what to do
then?

consider StringBuilder1. Append("my name is" + varName). Knowing this answer
is fundamentally important to me since I am building about 10,000 queries
that way and performance must always supercede anything else.

"Jon Skeet" <skeet@pobox.co m> wrote in message
news:MPG.19d4b8 f04604efcc9896f 7@news.microsof t.com...[color=blue]
> Alvin Bruney <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote:[color=green]
> > well for starters, i got this kind of construct peppered all over my[/color][/color]
code. i[color=blue][color=green]
> > start off with good intentions with the append but there seems to always[/color][/color]
be[color=blue][color=green]
> > a piece of string needing to be added and not worth the starting a new[/color][/color]
line.[color=blue][color=green]
> > i know that is so lazy. always figured the language was smart enough to[/color][/color]
know[color=blue][color=green]
> > better.[/color]
>
> Not sure exactly which construct you mean here, to be honest.
>[color=green]
> > i didn't care to read spec 14.15. what does it say in the queens[/color][/color]
english? do[color=blue][color=green]
> > i need to stop doing that (is really what i am asking)[/color]
>
> It says that "literal1"+"lit eral2" is always evaluated at compile-time
> to "literal1litera l2".
>
> --
> Jon Skeet - <skeet@pobox.co m>
> http://www.pobox.com/~skeet
> If replying to the group, please do not mail me too[/color]

[Jay B. Harlow [MVP - Outlook]]

Re: StringBuilder

Alvin,
See my & Jon's responses to Michael Meyer.
[color=blue]
> consider StringBuilder1. Append("my name is" + varName). Knowing this[/color]
answer[color=blue]
> is fundamentally important to me since I am building about 10,000 queries
> that way and performance must always supercede anything else.[/color]
You will have 10,000 temporary string objects on the heap that will need to
be collection. If you are concatenating more then 3 objects or 4 strings you
will have that many temporary object arrays on the heap, in addition to the
temporary string object.

Hope this helps
Jay

"Alvin Bruney" <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote in
message news:uE3OmGsfDH A.3104@TK2MSFTN GP11.phx.gbl...[color=blue][color=green]
> > Not sure exactly which construct you mean here, to be honest.[/color]
> was talking about .append(blah + moreblah) as opposed to .append(blah);
> .append(morebla h)
>[color=green]
> > It says that "literal1"+"lit eral2" is always evaluated at compile-time
> > to "literal1litera l2".[/color]
>
> ok well that seems to be good for me then since it evaluates it at compile
> time. but what happens at run-time? what if literal2 was a string object
> (not interned) - as would frequently be the case. does it know what to do
> then?
>
> consider StringBuilder1. Append("my name is" + varName). Knowing this[/color]
answer[color=blue]
> is fundamentally important to me since I am building about 10,000 queries
> that way and performance must always supercede anything else.
>
> "Jon Skeet" <skeet@pobox.co m> wrote in message
> news:MPG.19d4b8 f04604efcc9896f 7@news.microsof t.com...[color=green]
> > Alvin Bruney <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote:[color=darkred]
> > > well for starters, i got this kind of construct peppered all over my[/color][/color]
> code. i[color=green][color=darkred]
> > > start off with good intentions with the append but there seems to[/color][/color][/color]
always[color=blue]
> be[color=green][color=darkred]
> > > a piece of string needing to be added and not worth the starting a new[/color][/color]
> line.[color=green][color=darkred]
> > > i know that is so lazy. always figured the language was smart enough[/color][/color][/color]
to[color=blue]
> know[color=green][color=darkred]
> > > better.[/color]
> >
> > Not sure exactly which construct you mean here, to be honest.
> >[color=darkred]
> > > i didn't care to read spec 14.15. what does it say in the queens[/color][/color]
> english? do[color=green][color=darkred]
> > > i need to stop doing that (is really what i am asking)[/color]
> >
> > It says that "literal1"+"lit eral2" is always evaluated at compile-time
> > to "literal1litera l2".
> >
> > --
> > Jon Skeet - <skeet@pobox.co m>
> > http://www.pobox.com/~skeet
> > If replying to the group, please do not mail me too[/color]
>
>[/color]

[mikeb]

Re: StringBuilder

Alvin Bruney wrote:[color=blue][color=green]
>>Not sure exactly which construct you mean here, to be honest.[/color]
>
> was talking about .append(blah + moreblah) as opposed to .append(blah);
> .append(morebla h)
>
>[color=green]
>>It says that "literal1"+"lit eral2" is always evaluated at compile-time
>>to "literal1litera l2".[/color]
>
>
> ok well that seems to be good for me then since it evaluates it at compile
> time. but what happens at run-time? what if literal2 was a string object
> (not interned) - as would frequently be the case. does it know what to do
> then?
>
> consider StringBuilder1. Append("my name is" + varName). Knowing this answer
> is fundamentally important to me since I am building about 10,000 queries
> that way and performance must always supercede anything else.[/color]

If the transient string objects that are created in calls like this are
an issue, there are a couple of ways to deal with the problem, while
keeping readability:

1) remember that StringBuilder.A ppend() returns the StringBuilder
instance. So you can make the above call like so:

StringBuilder1. Append( "my name is ").Append( varName);

whether this remains readable or not is a question of taste. It
does not create the transient string object, however.

2) write your own utility method that takes multiple strings to
append to a StringBuilder instance. Since StringBuilder is sealed, this
would likely be a static class - something like (untested code follows):

public class SbUtil {
public static StringBuilder Append( StringBuilder sb,
string s1,
string s2)
{
sb.Append( s1);
sb.Append( s2);
return( sb);
}
}

// ...

SbUtil.Append( StringBuilder1, "may name is ", varName);

[color=blue]
>
> "Jon Skeet" <skeet@pobox.co m> wrote in message
> news:MPG.19d4b8 f04604efcc9896f 7@news.microsof t.com...
>[color=green]
>>Alvin Bruney <vapordan_spam_ me_not@hotmail_ no_spamhotmail. com> wrote:
>>[color=darkred]
>>>well for starters, i got this kind of construct peppered all over my[/color][/color]
>
> code. i
>[color=green][color=darkred]
>>>start off with good intentions with the append but there seems to always[/color][/color]
>
> be
>[color=green][color=darkred]
>>>a piece of string needing to be added and not worth the starting a new[/color][/color]
>
> line.
>[color=green][color=darkred]
>>>i know that is so lazy. always figured the language was smart enough to[/color][/color]
>
> know
>[color=green][color=darkred]
>>>better.[/color]
>>
>>Not sure exactly which construct you mean here, to be honest.
>>
>>[color=darkred]
>>>i didn't care to read spec 14.15. what does it say in the queens[/color][/color]
>
> english? do
>[color=green][color=darkred]
>>>i need to stop doing that (is really what i am asking)[/color]
>>
>>It says that "literal1"+"lit eral2" is always evaluated at compile-time
>>to "literal1litera l2".
>>
>>--
>>Jon Skeet - <skeet@pobox.co m>
>>http://www.pobox.com/~skeet
>>If replying to the group, please do not mail me too[/color]
>
>
>[/color]

--
mikeb