C# way to mimic Python Dictionary Syntax
Is there a good way in C# to mimic the following python syntax:
mydict = {}
mydict["bc"] = {}
mydict["bc"]["de"] = "123"; # <-- This line
mydict["te"] = "5"; # <-- While also allowing this line
In other words, I'd like something with [] style access that can return either another dictionary or a string type, depending on how it has been set.
I've been trying to work this out with a custom class but can't seem to succeed. Any ideas?
Thanks!
Edit: I'm being evil, I know. Jared Par's solution is great . . . for a 2-level dictionary of this form. However, I am also curious about further levels . . . for instance,
mydict["bc"]["df"]["ic"] = "32";
And so on. Any ideas about that?
Edit 3:
Here is the final class I ended up using:
class PythonDict {
/* Public properties and conversions */
public PythonDict this[String index] {
get {
return this.dict_[index];
}
set {
this.dict_[index] = value;
}
}
public static implicit operator PythonDict(String value) {
return new PythonDict(value);
}
public static implicit operator String(PythonDict value) {
return value.str_;
}
/* Public methods */
public PythonDict() {
this.dict_ = new Dictionary<String, PythonDict>();
}
public PythonDict(String value) {
this.str_ = value;
}
public bool isString() {
return (this.str_ != null);
}
/* Private fields */
Dictionary<String, PythonDict> dict_ = null;
String str_ = null;
}
This class works for infinite levels, and can be read from without explicit conversion (dangerous, maybe, but hey).
Usage like so:
PythonDict s = new PythonDict();
s["Hello"] = new PythonDict();
s["Hello"]["32"] = "hey there";
s["Hello"]["34"] = new PythonDict();
s["Hello"]["34"]["Section"] = "Your face";
String result = s["Hello"]["34"]["Section"];
s["Hi there"] = "hey";
Thank you very much Jared Par!
Asked by: Arnold694 | Posted: 30-11-2021
Answer 1
You can achieve this by having the class, lets call it PythonDictionary, which is returned from mydict["bc"] have the following members.
- A indexer property to allow for the ["de"] access
- A implicit conversion from string to PythonDictionary
That should allow both cases to compile just fine.
For example
public class PythonDictionary {
public string this[string index] {
get { ... }
set { ... }
}
public static implicit operator PythonDictionary(string value) {
...
}
}
public void Example() {
Dictionary<string, PythonDictionary> map = new Dictionary<string, PythonDictionary>();
map["42"]["de"] = "foo";
map["42"] = "bar";
}
Answer 2
Thanks for posting this question and resolution. Converted to VB.NET:
Public Class PythonDict
' Public properties and conversions
Default Public Property Item(ByVal index As String) As PythonDict
Get
Return Me.dict_(index)
End Get
Set(value As PythonDict)
Me.dict_(index) = value
End Set
End Property
Public Shared Narrowing Operator CType(value As String) As PythonDict
Return New PythonDict(value)
End Operator
Public Shared Widening Operator CType(value As PythonDict) As String
Return value.str_
End Operator
' Public methods
Public Sub New()
Me.dict_ = New Dictionary(Of String, PythonDict)()
End Sub
Public Sub New(value As String)
Me.str_ = value
End Sub
Public Function isString() As Boolean
Return (Me.str_ IsNot Nothing)
End Function
' Private fields
Private dict_ As Dictionary(Of String, PythonDict) = Nothing
Private str_ As String = Nothing
End Class
Usage:
Dim s As PythonDict = New PythonDict()
s("Hello") = New PythonDict()
s("Hello")("32") = "hey there"
s("Hello")("34") = New PythonDict()
s("Hello")("34")("Section") = "Your face"
Dim result As String = s("Hello")("34")("Section")
s("Hi there") = "hey"
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