Convert Dictionary to List
This page was last reviewed on Apr 21, 2023.
Dot Net Perls
Convert Dictionary, List. A VB.NET Dictionary can be converted to a List. It can be represented as a List of KeyValuePairs. The ToList Function is useful here.
In converting Dictionaries and Lists, we have to understand that we may need to have KeyValuePairs. We demonstrate this conversion in the VB.NET language.
Convert List, Array
Example. We are acting on a Dictionary of String keys and Integer values, but these types can be changed. The Dictionary is a generic type, so it can be used with many key and value types.
Step 1 We create a Dictionary instance and set 4 different keys equal to four different values.
Step 2 Next, we call the ToList extension method on the Dictionary we just created.
Step 3 We can loop over each KeyValuePair in the List instance with a For-Each loop construct.
Module Module1 Sub Main() ' Step 1: create example dictionary. Dim dict As Dictionary(Of String, Integer) = New Dictionary(Of String, Integer)() dict("cat") = 1 dict("dog") = 2 dict("mouse") = 3 dict("palomino") = 4 ' Step 2: call ToList on it (use KeyValuePair list). Dim list As List(Of KeyValuePair(Of String, Integer)) = dict.ToList ' Step 3: we can loop over each KeyValuePair. For Each pair As KeyValuePair(Of String, Integer) In list Console.WriteLine(pair.Key) Console.Write(" ") Console.WriteLine(pair.Value) Next End Sub End Module
cat 1 dog 2 mouse 3 palomino 4
Discussion. Why would a programmer want to convert a Dictionary into a List? Looping over every element in a List is much faster than looping over all the pairs in a Dictionary.
And Lists will use less memory because no internal buckets array is necessary.
However On the other hand, Dictionary provides faster lookup and element removal.
Thus In most performance-sensitive programs that do key lookups, Dictionary is a better choice.
A summary. Here we converted a Dictionary into a List. A List of KeyValuePairs can always represent the data inside a Dictionary. The main difference between is performance.
Dot Net Perls is a collection of tested code examples. Pages are continually updated to stay current, with code correctness a top priority.
Sam Allen is passionate about computer languages. In the past, his work has been recommended by Apple and Microsoft and he has studied computers at a selective university in the United States.
This page was last updated on Apr 21, 2023 (simplify).
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