Is there a way to refer to an array element by string

Question

4.00/5 (1 vote)

See more:

Hey,

Does anybody know a way to make array (like in PHP) with a string reference:

$data["shopping"]["item1"] = "item name";

In vb.net I do it like

dim data(1,1) as string<br />
data(0,0)="item name"

but it's more difficult to read back the code...

I Know you have to define the array size before using in vb,
but is there a way to refer to an array element by string?

( data("shopping","item1")="item name" )

Thanks!!

Posted 19-May-11 2:10am

ArjanKempes

Add a Solution

3 solutions

Solution 1

I do not think that is possible. However, you might want to use a List(Of T)[^] or Dictionary(Of T)[^]. They are a bit more '.NETty' and easier to use. There is a small difference between Arrays and Lists(Of T), but when used correctly I don't think Arrays can do anything that Lists(Of T) can't. Of course some Array/List(Of T) pro will now prove me wrong... ;p

Edit, I understood my answer was not sufficiently explained:
If you use a Class with a unique ID you would probably only need a List(Of T) which you can then reference by its ID through, perhaps a LINQ query.

VB

Dim shoppingList As New List(Of ShoppingItem)
Dim item = (From i In shoppingList.Items Where i.ID = "item1").FirstOrDefault 'From the top of my head.

When you do need a Dictionary(Of T) you could use its Key as a string, in OP's case "ItemName" and a Class that represents Item. I doubt it is only a String. In most real world apps you'd have a Class.

VB

Dim shoppingDict As New Dictionary(Of String, ShoppingItem)
Dim item = shoppingDict.Item("ItemName") ' This returns the ShoppingItem Class with that item name.

If you would need an item which only has a string you should see cPallini's answer.

Posted 19-May-11 2:30am

Sander Rossel

Updated 19-May-11 12:05pm

v2

Comments

fjdiewornncalwe 19-May-11 10:31am

OP's answer moved to comment:
Tanks!! That's exactly what I was looking for!!

Sergey Alexandrovich Kryukov 19-May-11 16:50pm

Sorry, you failed to sat the truth. I just have to vote 1 in this case. This is QUITE POSSIBLE to implement. I advise to read my answer and remove yours.
Of course, if you think I miss something, tell me about it, I'll fix myself. But please keep in mind that I would be able to write sample implementation perfectly matching what OP wants (in C#, but VB.NET is perfectly the same, slightly different syntax).
--SA

Sander Rossel 19-May-11 17:59pm

The OP's question was "Is there a way to refer to an array element by string?" and I think we all agree that is not possible. As I said in my answer.
Using a Dictionary(Of T) is what I proposed instead.

I never said the OP should not use a Dictionary in a Dictionary, but if the OP is using Arrays then perhaps he does not know about Generics. Slapping him in the face with Dictionary(Of String, Dictionary(Of String, String)) might be a bit overwhelming at first. And getting the basics is, in my opinion, more important then getting a fully worked out example :)
I think you got downvoted because its to complex (don't you hate it when people downvote, but don't mention why...).
cPallini's answer is perfectly fine and quite in line with my answer. Just a bit more worked out.
I have edited my solution so it might be a bit more clear why I did not use a double Dictionary.
I hope you would reconsider your vote :)

Sergey Alexandrovich Kryukov 19-May-11 16:53pm

Oh, not need to write anything: C Pallini did that, please check his answer.
--SA

Simon_Whale 19-May-11 18:27pm

Nice answer +5 It shows that not all methodologies are transferable but there are always alternatives to use

Solution 4

This is possible using this indexer.
For some example, please see my code sample:
Location of a refernced object in an array?[^].

Please locate my second answer using Neuron this[].

The index can be anything, including the string. In your case, you need to have an instance of System.Collections.Generic.Dictionary behind. It will give you exact same semantics as with PHP. Double indexing you show is done like this: fist index returns some object using this indexer of string as well.

—SA

Posted 19-May-11 10:48am

Sergey Alexandrovich Kryukov

Comments

CPallini 20-May-11 3:10am

Downvote balanced. :-)

Sergey Alexandrovich Kryukov 20-May-11 3:19am

Well, thank you very much. Have no idea why such a low vote. However, my answer was redundant next to yours which was quite good.
--SA

CPallini 20-May-11 3:23am

Your Neuron class looks very interesting but beyond my current C# knowledge.

Sergey Alexandrovich Kryukov 20-May-11 23:26pm

Thank you.
I can't believe that. There is just two syntax ideas in that code: 1) indexers, 2) more than one indexer per class through the use of interface. One short paragraph in language description.
--SA

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Accepted Answer · 2011-05-19T02:50:00

Solution 2

Your best bet is probably a double Dictionary:

VB

Dim data As New Dictionary(Of String, Dictionary(Of String, String))

data("shopping") = New Dictionary(Of String, String)
data("shopping")("item1") = "item name"

Posted 19-May-11 2:50am

CPallini

Updated 19-May-11 2:52am

v3

Comments

[no name] 19-May-11 8:54am

Good. My 5 too.

CPallini 19-May-11 8:55am

Thank you.

Sergey Alexandrovich Kryukov 19-May-11 16:52pm

Correct, my 5. Please see my answer as well (probably it is redundant as your sample immediately works).
--SA

Sander Rossel 19-May-11 18:01pm

Nice answer. I understood that my answer was not sufficiently explained. I have improved it too.
My 5 for this.