C# Multidimensional Add

[Olias]

Hey guys 

i want do add something to a Multidimensional Dictionary.

But it doesn`t work.....

Would be rly nice if you could help me.

 

        private Dictionary<int, Dictionary<String, Boolean>> test = new Dictionary<int, Dictionary<string, bool>>(); 

// ins is a String

                test.Add(1, ins, false);

[Nuluvius]

A few things really: Foremost, you should be using code tags to present code here really. Secondly 'ins' is not a string. Finally you are attempting to add a discrete item representing multiple dimensions of the generic collection.

 

There's a few ways of accomplishing this; here's a simple console application demonstrating Initializer Syntax and adding at runtime:

using System;using System.Collections.Generic;namespace ConsoleApplication1{    class Program    {               static void Main(string[] args)        {            var initializerSyntaxTest = new Dictionary<int, Dictionary<string, bool>>                        {                            {                                1,                                new Dictionary<string, bool>                                    {                                        {                                            "Some string",                                            false                                        },                                        {                                            "Some other string",                                            true                                        }                                    }                            },                            {                                2,                                new Dictionary<string, bool>                                    {                                        {                                            "Another string",                                            true                                        },                                        {                                            "Another different string",                                            false                                        }                                    }                            }                        };            Console.WriteLine("Initializer Syntax Test:");            OutputStructure(initializerSyntaxTest);            Console.WriteLine();            Console.WriteLine();            var runtimeTest = new Dictionary<int, Dictionary<string, bool>>();            for (var i = 0; i < 10; i++)            {                var subDimension = new Dictionary<string, bool>();                for (var j = 0; j < 5; j++)                {                    subDimension.Add(Guid.NewGuid().ToString(), j % 2 == 0);                }                runtimeTest.Add(i, subDimension);            }            Console.WriteLine("Runtime Test:");            OutputStructure(runtimeTest);            Console.ReadKey();        }        private static void OutputStructure(Dictionary<int, Dictionary<string, bool>> input)        {            foreach (var kvp in input)            {                foreach (var subKvp in kvp.Value)                {                    Console.WriteLine("First dimension Key: {0}, second dimension Key: {1}, second dimension Value: {2}", kvp.Key, subKvp.Key, subKvp.Value);                }            }        }    }}

It should be noted that if you attempt to add something to the second dimension without initializing it first you will get a NullReferenceException.

[Gob]

First thing, try and put code into code tags.

 

I don't know C#, but I can guess what the issue is.

You are creating a dictionary that has String type keys, and Dictionary type values.

You correctly initialize the object:

private Dictionary<int, Dictionary<String, Boolean>> test = new Dictionary<int, Dictionary<String, Boolean>>();

But you are not correctly inserting a new entry into the dictionary:

// Can't do this, the ins String and False bool primative are not in a dictionary// test.Add(1, ins, false);//Initialize main dictionaryDictionary<int, Dictionary<String, Boolean>> main = new Dictionary<int, Dictionary<String, Boolean>>();int mainKey = 1;//Prep the Dictionary valueString subKey = "Some string key";Boolean subValue = false;Dictionary<String, Boolean> dictValue = new Dictionary<String, Boolean>();dictValue.Add(subKey,subValue);//Now Add to main dictmain.Add(mainKey,dictValue);

I hope this helps.

[fizzlesticks]

It should be noted that if you attempt to add something to the second dimension without initializing it first you will get a NullReferenceException.

And if you add the same item twice you will get an ArguementException.

 

So if the indices for the first dimension can't be done in a simple for loop at the start of the program, you'll need to keep checking if there is already an item with that key when you insert a new value. Something like:

private Dictionary<int, Dictionary<string, bool>> test = new Dictionary<int, Dictionary<string, bool>>();Dictionary<string, bool> subDict;if(test.TryGetValue(index, out subDict)){    subDict.Add("some string",false);}else{        subDict = new Dictionary<string,bool>();    subDict.Add("some string",false);    test.Add(index,subDict);}

[Nuluvius]

And if you add the same item twice you will get an ArguementException.

 

So if the indices for the first dimension can't be done in a simple for loop at the start of the program, you'll need to keep checking if there is already an item with that key when you insert a new value. Something like:

 

-code snip-

 

True! Also if one doesn't care then they can simply set or add an item by using the default index property demonstrated here.