add a single byte to byte()

[Guoqi Zheng]

I am really do not know so much about byte/bit, etc.

Question, if I defined a byte(), how can I add a single byte to it?

what I want is that I have an array of bytes, I loop that array, look at the
value of that individual byte, if that byte is what I want, then I insert it
into the new byte(). How can I do it?

--
Kind regards

Guoqi Zheng
guoqi AT meetholland dot com

Http://www.meetholland.com

[Hal Rosser]

Re: add a single byte to byte()

redim the array - and -
assign a byte to the new element

"Guoqi Zheng" <no@sorry.nl> wrote in message
news:%23F0557dl EHA.1936@TK2MSF TNGP12.phx.gbl. ..[color=blue]
> I am really do not know so much about byte/bit, etc.
>
> Question, if I defined a byte(), how can I add a single byte to it?
>
> what I want is that I have an array of bytes, I loop that array, look at[/color]
the[color=blue]
> value of that individual byte, if that byte is what I want, then I insert[/color]
it[color=blue]
> into the new byte(). How can I do it?
>
> --
> Kind regards
>
> Guoqi Zheng
> guoqi AT meetholland dot com
> Http://www.meetholland.com
>
>
>[/color]


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[Herfried K. Wagner [MVP]]

Re: add a single byte to byte()

* "Hal Rosser" <hmrosser@bells outh.net> scripsit:[color=blue]
> redim the array - and -
> assign a byte to the new element[/color]

In this case, 'ReDim Preserve' is the way to go.

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

[David]

Re: add a single byte to byte()

On 2004-09-08, Guoqi Zheng <no@sorry.nl> wrote:[color=blue]
> I am really do not know so much about byte/bit, etc.
>
> Question, if I defined a byte(), how can I add a single byte to it?
>
> what I want is that I have an array of bytes, I loop that array, look at the
> value of that individual byte, if that byte is what I want, then I insert it
> into the new byte(). How can I do it?[/color]

For resizable arrays, you really want to use
System.Collecti ons.ArrayList. You can always convert back into an
ordinary byte() after you've filled the ArrayList with the contents you
want.

If you only need to add a single byte one time, then ReDim Preserve will
work fine, but it sounds like you're doing this in a loop, and
performance will be terrible if you rely on ReDim here.

[Hal Rosser]

Re: add a single byte to byte()

Agreed
[color=blue]
> In this case, 'ReDim Preserve' is the way to go.
> />[/color]


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Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.754 / Virus Database: 504 - Release Date: 9/7/2004

[Cor Ligthert]

Re: add a single byte to byte()

Guaoqi,

Assume you have a text and want it to set as Asci in a byte array, than you
get something as (roughly typed in this message so watch typos)

\\\\
dim myString as string = "Ik hoop dat dit helpt?"
dim ByteArr(mystrin g.length) as byte
for i as integer = 0 to mystring.length -1
ByteArr(i) = Cbyte(asc(mystr string.substrin g(i,1)))
next
///

I hope this helps?

Cor

"Guoqi Zheng"
..[color=blue]
> I am really do not know so much about byte/bit, etc.
>
> Question, if I defined a byte(), how can I add a single byte to it?
>
> what I want is that I have an array of bytes, I loop that array, look at[/color]
the[color=blue]
> value of that individual byte, if that byte is what I want, then I insert[/color]
it[color=blue]
> into the new byte(). How can I do it?
>
> --
> Kind regards
>
> Guoqi Zheng
> guoqi AT meetholland dot com
> Http://www.meetholland.com
>
>
>[/color]

[Guoqi Zheng]

Re: add a single byte to byte()

Thanks, it sounds like exactly what I am looking for. An arraylist then back
to byte()

--
Kind regards

Guoqi Zheng
guoqi AT meetholland dot com

Http://www.meetholland.com

"David" <dfoster@woofix .local.dom> wrote in message
news:slrncjv5fg .aof.dfoster@wo ofix.local.dom. ..[color=blue]
> On 2004-09-08, Guoqi Zheng <no@sorry.nl> wrote:[color=green]
> > I am really do not know so much about byte/bit, etc.
> >
> > Question, if I defined a byte(), how can I add a single byte to it?
> >
> > what I want is that I have an array of bytes, I loop that array, look at[/color][/color]
the[color=blue][color=green]
> > value of that individual byte, if that byte is what I want, then I[/color][/color]
insert it[color=blue][color=green]
> > into the new byte(). How can I do it?[/color]
>
> For resizable arrays, you really want to use
> System.Collecti ons.ArrayList. You can always convert back into an
> ordinary byte() after you've filled the ArrayList with the contents you
> want.
>
> If you only need to add a single byte one time, then ReDim Preserve will
> work fine, but it sounds like you're doing this in a loop, and
> performance will be terrible if you rely on ReDim here.
>
>[/color]

[Jay B. Harlow [MVP - Outlook]]

Re: add a single byte to byte()

David,
Just be aware that an ArrayList with bytes in it is going to cause a lot of
boxing & unboxing which may hurt performance.

I would consider an array of bytes & ReDim Preserve, only over allocate the
array, then keep track of how many actual elements are in the array. By over
allocate I mean allocate 50 elements in the array although there is only 40
actual elements in it.

I will check if I have a good example. I have posted one or two examples
previously.

Hope this helps
Jay


"David" <dfoster@woofix .local.dom> wrote in message
news:slrncjv5fg .aof.dfoster@wo ofix.local.dom. ..[color=blue]
> On 2004-09-08, Guoqi Zheng <no@sorry.nl> wrote:[color=green]
>> I am really do not know so much about byte/bit, etc.
>>
>> Question, if I defined a byte(), how can I add a single byte to it?
>>
>> what I want is that I have an array of bytes, I loop that array, look at
>> the
>> value of that individual byte, if that byte is what I want, then I insert
>> it
>> into the new byte(). How can I do it?[/color]
>
> For resizable arrays, you really want to use
> System.Collecti ons.ArrayList. You can always convert back into an
> ordinary byte() after you've filled the ArrayList with the contents you
> want.
>
> If you only need to add a single byte one time, then ReDim Preserve will
> work fine, but it sounds like you're doing this in a loop, and
> performance will be terrible if you rely on ReDim here.
>
>[/color]

[Guoqi Zheng]

Re: add a single byte to byte()

This solution sounds fine as well.

But if I allocate 500 elements, and I used only 30, how can I remove the
extra 470 from that byte(), by Redim Preserve? and will these extra 470
elements cost performance problem?

--
Kind regards

Guoqi Zheng
guoqi AT meetholland dot com

Http://www.meetholland.com

"Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP @msn.com> wrote in message
news:%23o7HXMnl EHA.3968@TK2MSF TNGP11.phx.gbl. ..[color=blue]
> David,
> Just be aware that an ArrayList with bytes in it is going to cause a lot[/color]
of[color=blue]
> boxing & unboxing which may hurt performance.
>
> I would consider an array of bytes & ReDim Preserve, only over allocate[/color]
the[color=blue]
> array, then keep track of how many actual elements are in the array. By[/color]
over[color=blue]
> allocate I mean allocate 50 elements in the array although there is only[/color]
40[color=blue]
> actual elements in it.
>
> I will check if I have a good example. I have posted one or two examples
> previously.
>
> Hope this helps
> Jay
>
>
> "David" <dfoster@woofix .local.dom> wrote in message
> news:slrncjv5fg .aof.dfoster@wo ofix.local.dom. ..[color=green]
> > On 2004-09-08, Guoqi Zheng <no@sorry.nl> wrote:[color=darkred]
> >> I am really do not know so much about byte/bit, etc.
> >>
> >> Question, if I defined a byte(), how can I add a single byte to it?
> >>
> >> what I want is that I have an array of bytes, I loop that array, look[/color][/color][/color]
at[color=blue][color=green][color=darkred]
> >> the
> >> value of that individual byte, if that byte is what I want, then I[/color][/color][/color]
insert[color=blue][color=green][color=darkred]
> >> it
> >> into the new byte(). How can I do it?[/color]
> >
> > For resizable arrays, you really want to use
> > System.Collecti ons.ArrayList. You can always convert back into an
> > ordinary byte() after you've filled the ArrayList with the contents you
> > want.
> >
> > If you only need to add a single byte one time, then ReDim Preserve will
> > work fine, but it sounds like you're doing this in a loop, and
> > performance will be terrible if you rely on ReDim here.
> >
> >[/color]
>
>[/color]

[Cor Ligthert]

Re: add a single byte to byte()

Jay,

Your answer was my first answer as well, however I scratched it to make an
in my opinion nicer answer.

(I know it is not right to set a unicharacter to an asci value however as
sample goes this so easy)

The way you describe now is also in my opinion the best way to do it when
you do not know the length in advance.

Although an other alternative is of course doing it streaming.

:-)

Cor
[color=blue]
> David,
> Just be aware that an ArrayList with bytes in it is going to cause a lot[/color]
of[color=blue]
> boxing & unboxing which may hurt performance.
>
> I would consider an array of bytes & ReDim Preserve, only over allocate[/color]
the[color=blue]
> array, then keep track of how many actual elements are in the array. By[/color]
over[color=blue]
> allocate I mean allocate 50 elements in the array although there is only[/color]
40[color=blue]
> actual elements in it.
>
> I will check if I have a good example. I have posted one or two examples
> previously.
>
> Hope this helps
> Jay
>
>
> "David" <dfoster@woofix .local.dom> wrote in message
> news:slrncjv5fg .aof.dfoster@wo ofix.local.dom. ..[color=green]
> > On 2004-09-08, Guoqi Zheng <no@sorry.nl> wrote:[color=darkred]
> >> I am really do not know so much about byte/bit, etc.
> >>
> >> Question, if I defined a byte(), how can I add a single byte to it?
> >>
> >> what I want is that I have an array of bytes, I loop that array, look[/color][/color][/color]
at[color=blue][color=green][color=darkred]
> >> the
> >> value of that individual byte, if that byte is what I want, then I[/color][/color][/color]
insert[color=blue][color=green][color=darkred]
> >> it
> >> into the new byte(). How can I do it?[/color]
> >
> > For resizable arrays, you really want to use
> > System.Collecti ons.ArrayList. You can always convert back into an
> > ordinary byte() after you've filled the ArrayList with the contents you
> > want.
> >
> > If you only need to add a single byte one time, then ReDim Preserve will
> > work fine, but it sounds like you're doing this in a loop, and
> > performance will be terrible if you rely on ReDim here.
> >
> >[/color]
>
>[/color]

[Jay B. Harlow [MVP - Outlook]]

Re: add a single byte to byte()

Guoqi,[color=blue]
> extra 470 from that byte(), by Redim Preserve?[/color]
I would use Redim Preserve, Array.Copy, or Buffer.BlockCop y.
[color=blue]
> and will these extra 470
> elements cost performance problem?[/color]
1 allocation of 500 bytes followed by a Redim Preserve is going to perform
better then 30 Redim Preserves. And possible better then 30 boxes & unboxes.
The only real way to tell is to use a profiling tool to check.


Most of the time the overallocating will be the better performing (both
memory usage & speed wise). Sometimes the ArrayList & boxing may perform
acceptable.
Obviously if you know before hand how much space you will need or can make a
very good estimate you have a better chance of it.

Remember that reallocating (Redim preserve) in both cases means that a new
buffer needs to be defined, then the old buffer needs to be copied to the
new array.

Hope this helps
Jay


"Guoqi Zheng" <no@sorry.nl> wrote in message
news:%23kyIASnl EHA.2492@TK2MSF TNGP15.phx.gbl. ..[color=blue]
> This solution sounds fine as well.
>
> But if I allocate 500 elements, and I used only 30, how can I remove the
> extra 470 from that byte(), by Redim Preserve? and will these extra 470
> elements cost performance problem?
>
> --
> Kind regards
>
> Guoqi Zheng
> guoqi AT meetholland dot com
> Http://www.meetholland.com
>
> "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP @msn.com> wrote in message
> news:%23o7HXMnl EHA.3968@TK2MSF TNGP11.phx.gbl. ..[color=green]
>> David,
>> Just be aware that an ArrayList with bytes in it is going to cause a lot[/color]
> of[color=green]
>> boxing & unboxing which may hurt performance.
>>
>> I would consider an array of bytes & ReDim Preserve, only over allocate[/color]
> the[color=green]
>> array, then keep track of how many actual elements are in the array. By[/color]
> over[color=green]
>> allocate I mean allocate 50 elements in the array although there is only[/color]
> 40[color=green]
>> actual elements in it.
>>
>> I will check if I have a good example. I have posted one or two examples
>> previously.
>>
>> Hope this helps
>> Jay
>>
>>
>> "David" <dfoster@woofix .local.dom> wrote in message
>> news:slrncjv5fg .aof.dfoster@wo ofix.local.dom. ..[color=darkred]
>> > On 2004-09-08, Guoqi Zheng <no@sorry.nl> wrote:
>> >> I am really do not know so much about byte/bit, etc.
>> >>
>> >> Question, if I defined a byte(), how can I add a single byte to it?
>> >>
>> >> what I want is that I have an array of bytes, I loop that array, look[/color][/color]
> at[color=green][color=darkred]
>> >> the
>> >> value of that individual byte, if that byte is what I want, then I[/color][/color]
> insert[color=green][color=darkred]
>> >> it
>> >> into the new byte(). How can I do it?
>> >
>> > For resizable arrays, you really want to use
>> > System.Collecti ons.ArrayList. You can always convert back into an
>> > ordinary byte() after you've filled the ArrayList with the contents you
>> > want.
>> >
>> > If you only need to add a single byte one time, then ReDim Preserve
>> > will
>> > work fine, but it sounds like you're doing this in a loop, and
>> > performance will be terrible if you rely on ReDim here.
>> >
>> >[/color]
>>
>>[/color]
>
>[/color]

[David]

Re: add a single byte to byte()

On 2004-09-09, Jay B. Harlow [MVP - Outlook] <Jay_Harlow_MVP @msn.com> wrote:[color=blue]
> David,
> Just be aware that an ArrayList with bytes in it is going to cause a lot of
> boxing & unboxing which may hurt performance.[/color]

Actually, it wouldn't cause a lot of either, just once per byte, which
is trivial unless you're dealing with huge nested loops. Overallocating
an array is faster, but unless you are absolutely sure you'll never need
a larger array (and that might be the case here), what should be a very
simple loop starts looking much uglier than it needs to be.

Aren't you the one who constantly posts the 80/20 rule here, or am I
confusing you with somebody else?

[Jay B. Harlow [MVP - Outlook]]

Re: add a single byte to byte()

David,[color=blue]
> Aren't you the one who constantly posts the 80/20 rule here, or am I
> confusing you with somebody else?[/color]

Yes I am. Which is why I stated "may hurt performance", then again today I
added to "the only real way to tell is to use a profiling tool to check".
[color=blue][color=green]
>> Just be aware that an ArrayList with bytes in it is going to cause a lot
>> of
>> boxing & unboxing which may hurt performance.[/color]
>
> Actually, it wouldn't cause a lot of either, just once per byte, which
> is trivial unless you're dealing with huge nested loops.[/color]
Correct. You will have a box for each byte you put into the ArrayList. Plus
an Unbox for each byte you remove.

So if you have a lot of bytes you will have a lot of boxing. In other words
at least 1 box & unbox for each byte. Correct?

Hope this helps
Jay



"David" <dfoster@woofix .local.dom> wrote in message
news:slrnck1ivm .dal.dfoster@wo ofix.local.dom. ..[color=blue]
> On 2004-09-09, Jay B. Harlow [MVP - Outlook] <Jay_Harlow_MVP @msn.com>
> wrote:[color=green]
>> David,
>> Just be aware that an ArrayList with bytes in it is going to cause a lot
>> of
>> boxing & unboxing which may hurt performance.[/color]
>
> Actually, it wouldn't cause a lot of either, just once per byte, which
> is trivial unless you're dealing with huge nested loops. Overallocating
> an array is faster, but unless you are absolutely sure you'll never need
> a larger array (and that might be the case here), what should be a very
> simple loop starts looking much uglier than it needs to be.
>
> Aren't you the one who constantly posts the 80/20 rule here, or am I
> confusing you with somebody else?
>
>[/color]

[Cor Ligthert]

Re: add a single byte to byte()

David,
[color=blue]
> Aren't you the one who constantly posts the 80/20 rule here, or am I
> confusing you with somebody else?[/color]

And the other one in other words is me. I am the one who uses almost the
arraylist in samples for everything while others point mostly than too the
hashtable, (where I use than when it is needed earlier the sortedlist).

When it is about a byte array, than there should be a reason why it is a
byte array, because it is in my opinion an archaic piece of storage, altough
very good for serializing and deserializing. For those you loads the
bytearray streaming and you do not need to set a byte by byte to an array.

You can see in this thread a message from me which describes a bytearray
with ASCI chareacter, however for what I would directly use an arraylist
when it was really needed to get the full unicode in a char. (Although I
really cannot find a reason for that)

In my idea in this case when there is really a bytearray needed, than we
should never go to the arraylist, because than the one who does that has
never investigated his problem. Because the byte is the value type you take
as last to choose from when it is not streaming.

However when it should be a bytearray and you do not know the size however
know that the maximum is 400bytes, than you should not even redim it.
Probably you will loose with the code to redim more bytes than what you can
earn with that.

However just my idea.

Cor

[David]

Re: add a single byte to byte()

On 2004-09-09, Jay B. Harlow [MVP - Outlook] <Jay_Harlow_MVP @msn.com> wrote:[color=blue]
> David,[color=green]
>> Aren't you the one who constantly posts the 80/20 rule here, or am I
>> confusing you with somebody else?[/color]
>
> Yes I am. Which is why I stated "may hurt performance", then again today I
> added to "the only real way to tell is to use a profiling tool to check".
>[color=green][color=darkred]
>>> Just be aware that an ArrayList with bytes in it is going to cause a lot
>>> of
>>> boxing & unboxing which may hurt performance.[/color]
>>
>> Actually, it wouldn't cause a lot of either, just once per byte, which
>> is trivial unless you're dealing with huge nested loops.[/color]
> Correct. You will have a box for each byte you put into the ArrayList. Plus
> an Unbox for each byte you remove.
>
> So if you have a lot of bytes you will have a lot of boxing. In other words
> at least 1 box & unbox for each byte. Correct?[/color]

Yep, it increases O(n) as the number of bytes increases. It's a rare
app where such a thing is a major concern. Though, certainly, such apps
are out there.