CODEWITHSUNDEEP
vb.netlist
sheach
sheach

Reputation: 65

Get a value from a 2 dimensional list

Well I dont realy know if this is a 2 dimensional list but I will ask anyway.

So I have this:

Dim list = New List(Of KeyValuePair(Of String, Integer))
    list.Add(New KeyValuePair(Of String, Integer)("Tony", 16))
    list.Add(New KeyValuePair(Of String, Integer)("George", 19))

How can i get just the value from "Tony" ? or "George"?

Upvotes: 0

Views: 2209

Answers (3)

Asif Ali
Asif Ali

Reputation: 1

I suggest to use dictionary of KeyValue pair instead of List of KeyValue pair.You will have an advantage that you can check whether a key exists without iterating dictionary. If key exists you can get its value. Here's how you can do it. 

Dim dict As New Dictionary(Of String, Integer)
Dim keyvalue As Integer=0
dict.Add("Jhon",47)
dict.Add("Zara",21)
if(dict.ContainsKey("Jhon")){
keyvalue = dict("Jhon")
}

While for List you will have to iterate until you find key.

Upvotes: 0

Steven Doggart
Steven Doggart

Reputation: 43743

No, that's not really what people mean when they refer to a 2D array. It's just a list of objects where each object has multiple properties. In any case, typically KeyValuePair objects are used in Dictionary lists rather than a simple List(Of T) list. Since the Dictionary object is implemented as a hash-table, it makes it very easy and efficient to access the items via their key value (i.e. name). So, for instance, if you used a dictionary like this:

Dim dict As New Dictionary(Of String, Integer)()
dict.Add("Tony", 16)
dict.Add("George", 19)

Then you could access the "Tony" item like this:

Dim age As Integer = dict("Tony")

But if you must use a List(Of KeyValuePar) objects, then you would just need to loop through them to find the matching item, like this:

Dim match As KeyValuePair = Nothing
For Each i As KeyValuePair In list
    If i.Key = "Tony" Then
        match = i
        Exit For
    End If
Next
Dim age As Integer = match.Value

But LINQ does make that a bit easier:

Dim age As Integer = list.First(Function(x) x.Key = "Tony").Value

Upvotes: 2

Caio César S. Leonardi
Caio César S. Leonardi

Reputation: 536

list.Item(0).Key will get the key "Tony"

list.Item(0).Value will get the value 16

and

list.Item(1).Key will get the key "George"

list.Item(1).Value will get the value 19

Upvotes: 0

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