questions about arrays and collections

H,
>
i'm starting with asp.net/vb.net and have some questions about arrays and
collections:
>
1) what's the difference between:
dim x() as string
and
dim x as array

2) can variable 'x' in the second case contain anything (string, integer
... together)?

3) what is the correct syntax?
dim x as arraylist
or
dim x as arraylist()

4) what to choose between:
dim x as array (or if no difference dim x() )
and
dim x as arraylist

5) what to choose between:
dim x as arraylist
and
dim x as list(of string)

Gilbert wrote:>
The difference is that the first one is a reference to a string array,
while the second one is a reference to any kind of array.
>>
Yes, and no. The reference can be used for any kind of array. If you
assign it an array of strings, you can only put strings in that array. If
you on the other hand assigns it an array of Object, you can put anything
in the array.
>>
That depends on what you want to do. The first one declares a reference to
an ArrayList, the second one declares a reference to an array of ArrayList
objects.
>>
Again, that depends on what you want to do. The first one declares a
reference to an array (of any type). The second one declares a reference
to an ArrayList.
>
An ArrayList is good if you want a list that grows dynamically. An array
can not be resized.
>
If you are using frameword 2.0, you can use a generi list instead of an
ArrayList (unless you want to mix data types in the list). Generics has
made ArrayList almost obsolete.
>>
Guess what? It depends on what you want to do. ;)
>
An ArrayList is equivalent to a List(Of Object). If you want a list where
you can mix data types, that is what you can use. If you only want to put
strings in the list, you should definitely choose the second one.
>
>
--
Göran Andersson
_____
http://www.guffa.com

1)dim x as string() = dim x() as string = an array of string ?
>

2) dim x as array() = an array of array? Is this the same as dim x( , )?
>
>

Thanks for your explanation.
If you don't mind, 2 more questions ...
>
1)dim x as string() = dim x() as string = an array of string ?

2) dim x as array() = an array of array? Is this the same as dim x( , )?

The first one is the new syntax,

Very little correction on your for the rest very fine explanation.
>>
The first is a new syntax,
>
Cor
>

Very little correction on your for the rest very fine explanation.
>>
The first is a new syntax,
>
Cor
>
>

Indeed. Thanks a lot.
And ... i swear: this is my last question:
Look at this: the first Dim works, the second doesn't: (error)
What do i create with the second Dim and how to use it?
>
Dim r As Array = Array.CreateInstance(GetType(Int32), 101)
r(0) = 3
r(100) = 5
>
Dim az As Array() = Array.CreateInstance(GetType(Int32), 101)
az(0) = 3
az(100) = 5
>

Gilbert wrote:>
The second one declares a reference to an array of arrays, then you create
an array of integer and try to assign it to the reference. The reference
is for an array and the object is an array, but the data type of the
arrays differ. Here's how you create an integer array:
>
Dim az as Integer() = New Integer(100)
or:
Dim az as Integer() = Array.CreateInstance(GetType(Int32), 101)
>
or, just for completeness, using the old syntax:
>
Dim az() as Integer = New Integer(100)
or:
Dim az() as Integer = Array.CreateInstance(GetType(Int32), 101)
>
--
Göran Andersson
_____
http://www.guffa.com

Cor Ligthert [MVP] wrote:>
I don't understand how that is a correction?
>
You removed "one" which makes it implied, but it's still there.
>
Then you changed "the new" to "a new", which doesn't change the meaning of
the sentence either.
>
So, what's the difference?
>
--
Göran Andersson
_____
http://www.guffa.com

Goran,
>
"The" new in the sentence as it is used, gives the idea that it replaces;
"a" new means that it is an addition, very simple in my opinion. Both are
completely valid, there is not any idea of replacing

and there is not any
preference for one of those, so there is not a "the" new.

>
Cor
>
"Göran Andersson" <guffa@guffa.comschreef in bericht
news:%23AETpjNWHHA.1016@TK2MSFTNGP04.phx.gbl...>
>

Oh, yes, there is a preference. I prefer the new syntax, but that is of
course only my own preference. :)
>