position in array using a string

[Tim]

hi all,

not quite sure how to ask this, but here goes...

I have an array of values

a(0)="SMITH"
a(1)="JOHN"

I need to be able to reference each element using a string...

a("lastname") should return "SMITH"
a("firstname" ) should return "JOHN"

in much the same way as referencing a control in a collection of
controls, or an item in a collection of items.

any clues on how to achieve this?

(of course, everything is dynamic. I don't know that "lastname" and
"firstname" even exist before runtime)

cheers

[Larry Lard]

Re: position in array using a string


Tim wrote:[color=blue]
> hi all,
>
> not quite sure how to ask this, but here goes...
>
> I have an array of values
>
> a(0)="SMITH"
> a(1)="JOHN"
>
> I need to be able to reference each element using a string...
>
> a("lastname") should return "SMITH"
> a("firstname" ) should return "JOHN"
>
> in much the same way as referencing a control in a collection of
> controls, or an item in a collection of items.
>
> any clues on how to achieve this?[/color]

The general name for the type of collection that achieves this is
"dictionary ". A real-world dictionary maps 'words' to 'meanings' - in
..NET we say a dictionary maps 'keys' to 'values'. Both keys and values
can be of any type you like. Here both keys and values would be of type
String.

In 1.x (VB2002/3) you could just use a Hashtable, or to enforce strict
typing derive your own class from DictionaryBase (both in
System.Collecti ons).

In 2.0 (VB2005) use Dictionary(Of String,String) from
System.Collecti ons.Generic.

--
Larry Lard
Replies to group please

[Tim]

Re: position in array using a string

dictionary heh (2005), I'll investigate further.

many thanks.

any sample code?

cheers

[Larry Lard]

Re: position in array using a string


Tim wrote:[color=blue]
> dictionary heh (2005), I'll investigate further.
>
> many thanks.
>
> any sample code?[/color]

There's an example in the main doc topic for Dictionary(Of K,V) at

<http://msdn2.microsoft .com/en-us/library/xfhwa508(VS.80) .aspx>

--
Larry Lard
Replies to group please

[Cor Ligthert [MVP]]

Re: position in array using a string

Tim,

As alternative not so nice done

\\\
Public Class Test
Public Shared Sub Main()
Dim a As New List(Of names)
a.Add(New names("John", "Smith"))
MessageBox.Show (a(0).mFirstnam e & " " & a(0).mLastname)
End Sub
End Class
Public Class names
Public mLastname As String 'should be as properties
Public mFirstname As String 'should be as properties
Public Sub New(ByVal firstname As String, _
ByVal lastname As String)
mLastname = lastname
mFirstname = firstname
End Sub
End Class
///

I hope this helps,

Cor


"Tim" <Citizen10Bears @gmail.com> schreef in bericht
news:1145948457 .981755.228670@ e56g2000cwe.goo glegroups.com.. .[color=blue]
> hi all,
>
> not quite sure how to ask this, but here goes...
>
> I have an array of values
>
> a(0)="SMITH"
> a(1)="JOHN"
>
> I need to be able to reference each element using a string...
>
> a("lastname") should return "SMITH"
> a("firstname" ) should return "JOHN"
>
> in much the same way as referencing a control in a collection of
> controls, or an item in a collection of items.
>
> any clues on how to achieve this?
>
> (of course, everything is dynamic. I don't know that "lastname" and
> "firstname" even exist before runtime)
>
> cheers
>[/color]

[Tim]

Re: position in array using a string

thanks guys, dictionary works a treat. I think this will get a lot of
use!