var for_cat_dict = new Dictionary<string, string>();
var category_Dict = new Dictionary<string,Dictionary<string,string>>();
for_cat_dict.Add(bean.getId(), bean.getId());
Now I want to add elements to the category_dict. So I tried..
category_Dict.Add(bean.getId(),[for_cat_dict]);
But it doesnt work... any solutions??
It's not really clear what you're trying to do, but
Category_Dict.Add(bean.getId(), for_cat_dict);
should at least compile. Whether it'll do what you want is another matter - it's not clear whether these are local variables, fields etc. (It also looks like you're not following .NET naming conventions in various ways...)
Dictionary<string, string> for_cat_dict = new Dictionary<string, string>();
Dictionary<string, Dictionary<string, string>> Category_Dict = new Dictionary<string, Dictionary<string, string>>();
Category_Dict.Add("somekey", for_cat_dict);
Related
I need to know how to access and initialize a series of Dictionaries containing other dictionaries.
For example, if I have
class Conv{
Dictionary<int, Dictionary<int, Dictionary<int, List<double>>>> valori;
}
And I want to initiate the parameter "valori" with random numbers, how can I do it?
I would do it like
valori[n1].Values[n2].Values[n3]
But after the first "Value", MVS gives me an error. Maybe I have to allocate the memory first? I learned a little bit of c++, but I'm still new to c#
Also let me know if I forgot something important in my question
You need to create the sub-dictionaries for each key before using them
var list = new List<double> {d};
var d1 = new Dictionary<int, List<double>> {{n3, list }};
var d2 = new Dictionary<int, Dictionary<int, List<double>>> {{n2, d1}};
valori[n1] = d2;
You can also write this short in one line:
valori[n1] = new Dictionary<int, Dictionary<int, List<double>>> {{n2, new Dictionary<int, List<double>> {{n3, new List<double> {d}}}}};
When all dictionaries are actually created you can access them normally:
var savedList = valori[n1][n2][n3];
Since this syntax is very clunky and it is easy to make a mistake (missing if a sub-dictionary exists, overriding data, etc), I'd strongly suggest changing the datastructure or at least hiding it in a dedicated class
Maybe i'm mistaken but I can't think of situation that you would need this kind of structure but nevertheless here's my help:
First of all you need to assign the variable or you will get the error :
"Use of unassign local variable".So the code will be like:
Dictionary<int, Dictionary<int, Dictionary<int, List<double>>>> valori=new
Dictionary<int, Dictionary<int, Dictionary<int, List<double>>>>();
Secondly you need to add some data to the dictionary in order to use it later so
you should do :
valori.Add(2, new Dictionary<int, Dictionary<int, List<double>>>());
valori.Add(3, new Dictionary<int, Dictionary<int, List<double>>>());
valori.Add(4, new Dictionary<int, Dictionary<int, List<double>>>());
"notice that keys are different"
And instead of new Dictionary<int, Dictionary<int, List<double>>>() you should
enter a value of that type.
In C#, what is the syntax for instantiating and initializing a dictionary containing as values an array of dictionaries, those dictionaries themselves containing arrays as values?
For example, (I believe),
Dictionary<string, Dictionary<string, string[]>[]>?
Here's an example of what I'm trying to do:
private static readonly Dictionary<string, Dictionary<string, DirectoryInfo[]>[]> OrderTypeToFulfillmentDict = new Dictionary<string, Dictionary<string, DirectoryInfo[]>>()
{
{"Type1", new []
{
ProductsInfo.Type1FulfillmentNoSurfacesLocations,
ProductsInfo.Type2FulfillmentSurfacesLocations
}
}
}
where Type1Fulfillment..., and Type2Fulfillment... are already constructed as
Dictionary<string, DirectoryInfo[]>.
This throws the following compiler error:
"Cannot convert from System.Collections.Generic.Dictionary<string, System.IO.DirectoryInfo[]>[] to System.Collections.Generic.Dictionary<string, System.IO.DirectoryInfo[]>"
Edit: The problem was, as Lanorkin pointed out, that I was missing the final [] in the new Dictionary<string, Dictionary<string, DirectoryInfo[]>>(). Still, it goes without saying that this probably isn't something anyone should be trying to do in the first place.
What you've got looks correct, but what you're doing has a real code smell about it that's going to lead to some serious technical debt.
For starters, rather than having an inner Dictionary<string, string[]> model this in a class with methods appropriate to what you're trying to model. Otherwise anyone accessing this type isn't going to have a clue about what it's really modeling.
Something like this:
var dic = new Dictionary<string, Dictionary<int, int[]>[]>
{
{
"key1",
new[]
{
new Dictionary<int, int[]>
{
{1, new[] {1, 2, 3, 4}}
}
}}
};
Dictionary<string, Dictionary<string, string[]>[]> complexDictionary = new Dictionary<string, Dictionary<string, string[]>[]>();
or using the var keyword:
var complexDictionary = new Dictionary<string, Dictionary<string, string[]>[]>();
The following is perfectly valid
// array of dictionary
Dictionary<int, string[]>[] matrix = new Dictionary<int, string[]>[4];
//Dictionary of string and dictionary array
Dictionary<string, Dictionary<string, string[]>[]> dicOfArrays= new Dictionary<string, Dictionary<string, string[]>[]>();
private static readonly Dictionary<string, Dictionary<string, DirectoryInfo[]>>
OrderTypeToFulfillmentDict = new Dictionary<string, Dictionary<string, DirectoryInfo[]>>()
{
{"Type1", new []
{
ProductsInfo.Type1FulfillmentNoSurfacesLocations,
ProductsInfo.Type2FulfillmentSurfacesLocations
}
}
}
You have the wrong type in your variable definition. Remove the final "[]" as you don't want an array of dictionaries.
I'm trying to hold a lobby system inside of a dictionary.
private Dictionary<string, Dictionary<string, string>> lobbys;
The first string being the Lobby ID, and the dictionary within the dictionary holding the clients usernames in the lobby.
When I try to create a new 'lobby' in the dictionary like so:
lobbys.Add("dSd244SfasdD", null);
( the "dSd244SfasdD" being the unique lobby ID, and null being the null dictionary I've yet to create (since theres no users in it yet))
I get this error: "Object referenced not set to an instance of an object."
I'm unsure as to what I'm doing wrong, and I'm fairly new to C#. Please help. Thanks :)
You must first instantiate the lobbys Dictionary (which holds the Dictionaries):
lobbys = new Dictionary<string, Dictionary<string, string>>();
Then you can add to this lobbys, and when you do so, you should instantiate those inner dictionaries.
lobbys.Add("dsD244SfasD", new Dictionary<string, string>());
Then, when you add to those inner dictionaries:
lobbys["dsD244fasD"].Add("Client1", "Bob Jones");
lobbys["dsD244fasD"].Add("Client2", "Bill James");
You need to instantiate your dictionary.
lobbys = new Dictionary<string, Dictionary<string, string>();
If its a field in your class, you can initialize it at Field or you can initialize it in the class constructor.
You haven't assigned a value to your variable, so it's got the default value of null. (Don't forget that the value of lobbys isn't an object - it's a reference). You could either assign it a value in your constructor, or in the declaration:
private Dictionary<string, Dictionary<string, string>> lobbys
= new Dictionary<string, Dictionary<string, string>>();
(You may well want to make it a readonly variable at the same time - that wouldn't stop you from changing the dictionary's contents, but it would mean that the variable would always refer to the same dictionary.)
You need create an instance of the object first before use it.
private Dictionary<string, Dictionary<string, string>> lobbys = new Dictionary<string, Dictionary<string, string>>();
private Dictionary<string, Dictionary<string, string>> lobbys
= new Dictionary<string, Dictionary<string, string>>();
I have tried reading the other posts on this subject and can't quite figure this out.
I have a list in C# that I want to put in a dictionary with all of the same keys. The list is this
string[] IN ={"Against","Like","Upon","Through","Of","With","Upon","On","Into","From","by","that","In","About","For"
,"Along","Before","Beneath","At","Across","beside","After","Though","Among","Toward","If"};
I want to create and populate a dictionary with the key being "IN" (the name of the array) and then having each string for the array in the dictionary.
This is what I wrote to create the dictionary (which I am not sure is correct):
Dictionary<string, List<string>> wordDictionary = new Dictionary<string, List<string>> ()
But I am not sure how to populate the dictionary.
Any help would be greatly appreciated as this is the first time I have tried to use a dictionary and I am new to C#
An array is string[], not List<string>, so just do this:
Dictionary<string, string[]> wordDictionary = new Dictionary<string, string[]>();
Now you can add your array as usual.
wordDictionary.Add("IN", IN);
Or:
wordDictionary.Add("IN", new string[] {"Against","Like","Upon","Through","Of","With","Upon","On","Into","From","by","that","In","About","For","Along","Before","Beneath","At","Across","beside","After","Though","Among","Toward","If"});
Dictionary.Add("IN", new List<string>(IN));
...if you want to keep the current signature for your dictionary.
If you change it to Dictionary<string, string[]> then you can just:
Dictionary.Add("IN",IN);
You currently have a string array, not a list - so it should be:
Dictionary<string, string[]> wordDictionary = new Dictionary<string,string[]> ()
Then you can just add items like:
wordDictionary.Add("IN" , IN);
Do you really need to convert your array into a string? You could very well use string[] instead of List in your dictionary:
var wordDictionary = new Dictionary<string, string[]>();
wordDictionary.Add("IN", IN);
But if you really want to convert your string array to List:
var wordDictionary = new Dictionary<string, List<string>>();
wordDictionary.Add("IN", IN.ToList());
Another way to add the array (it's not a list) to the dictionary is to use collection initializer:
var wordDictionary = new Dictionary<string, string[]> { "IN", IN };
This is exactly the same as creating the dictionary in a normal way and then calling Add("IN", IN).
I would like to use Dictionary as TKey in another Dictionary. Something similar to python. I tried this but it gives me errors.
Dictionary<Dictionary<string, string>, int> dict = new Dictionary<Dictionary<string, string>, int>();
Dictionary<string, string> dict2 = new Dictionary<string, string>();
dict2["abc"] = "def";
dict[dict["abc"] = 20;
What error is it giving you? Is it complaining about your missing bracket on line 4?
Line 4 looks like it should be:
dict[dict["abc"]] = 20;
However, you probably mean this, since "abc" is not a key of dict:
dict[dict2["abc"]] = 20;
But dict2["abc"] is a string, when the key of dict is supposed to be a Dictionary<string, string>.
But let's re-examine your original goal at this point before going to far down this path. You shouldn't be using mutable types as dictionary keys in the first place.
This may be the code you're looking for:
Dictionary<string, int> dict = new Dictionary<string, int>();
Dictionary<string, string> dict2 = new Dictionary<string, string>();
dict2["abc"] = "def";
dict[dict2["abc"]] = 20;
But it's hard to tell for sure.
Just to throw this in there, I often find that dealing with complicated dictionaries like you describe it's far better to use real names with them rather than trying to let the reader of the code sort it out.
You can do this one of two ways depending on personal preference. Either with a using statement to create a complier alias. Note you have to use the fully qualified type name since this is a compiler alias.
using ComplexKey = System.Collections.Generic.Dictionary<String, String>;
using ComplexType = System.Collections.Generic.Dictionary<
System.Collections.Generic.Dictionary<String, String>,
String
>;
Or you can go the full blown type way and actually create a class that inherits from Dictionary.
class ComplexKey : Dictionary<String, String> { ... }
class ComplexType : Dictionary<ComplexKey, String> { ... }
Doing this will make it far easier for both you and the reader of your code to figure out what you're doing. My general rule of thumb is if I'm creating a generic of a generic it's time to look at building some first class citizens to represent my logic rather.
It's because the "dict["abc"] is not dictionary, but "string".
The correct, what you asked is:
Dictionary<Dictionary<string, string>, int> dict = new Dictionary<Dictionary<string, string>, int>();
Dictionary<string, string> dict2 = new Dictionary<string, string>();
dict2["abc"] = "def";
dict[dict2] = 20;
But i'm not sure, this is what you realy want/need.