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1. Top results related to eight function of dictionary in c# 3 string

   • Dictionary Of Dictionaries in C#

     Top Answer

     Answered Dec 08, 2016 · 8 votes

     You can fill the dictionary directly in your loop

     private Dictionary<string, Dictionary<string, Dictionary<string, string>>> zooDict = new Dictionary<string, Dictionary<string, Dictionary<string, string>>>();-while (reader.Read()){ var location = reader.GetString(0).Trim(); var animal= reader.GetString(1).Trim(); var Monday= reader.GetValue(1).ToString().Trim(); var Tuesday= reader.GetValue(3).ToString().Trim(); if(!zooDict.ContainsKey(location)) zooDict[location] = new Dictionary<string, Dictionary<string, string>>(); zooDict[location][animal] = new Dictionary<string, string>() { { "MN", Monday }, { "Tu", Tuesday } };}

     As a side note, you might want to consider creating classes to represent your objects, add them to a dictionary or list, and use Newtonsoft Json.net (http://www.newtonsoft.com/json) to serialize them instead of using dictionaries for everything. For example, you can create a class:

     public class Animal{ public string Name { get; set; } public int Monday { get; set; } public int Tuesday { get; set; }}var zooDict = new Dictionary<string, List<Animal>>();// then in your while loop you do this if(!zooDict.ContainsKey(location)) zooDict[location] = new List<Animal>();zooDict[location].Add(new Animal() { /* fill Monday and Tuesday properties */ });

     Of course, you can take this one step further and create a class with properties string Location and List<Animal> Animals, and eliminate dictionaries altogether. It depends on your use case(s) I guess

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     1/5

   • C# Find every number divisible by 3, in a string of numbers

     Top Answer

     Answered Sep 17, 2021 · 3 votes

     This is still vulnerable to overflows, but it would take a very long string indeed to reach that point:

     class Program{ static void Main(string[] args) { Console.Write("Enter a string of numbers: "); string Nums = Console.ReadLine(); Console.WriteLine("The following numbers are divisble by 3: "); foreach(var result in DivisibleByThree(Nums)) { Console.WriteLine(result); } Console.ReadKey(true); } public static IEnumerable<string> DivisibleByThree(string input) { for (int i = 0; i < input.Length; i++) { for(int j = input.Length; j > i; j--) { string segment = input.Substring(i, j-i); if (SumOfDigits(segment) % 3 == 0) { yield return segment; } } } } public static int SumOfDigits(string digits) { return digits.Where(c => char.IsDigit(c)).Select(c => c-'0').Sum(); }}

     See it work here:

     https://dotnetfiddle.net/KacyAD

     And since someone suggested recursion, I thought that'd be fun to try. I didn't quite get as far as I wanted (removing both loops and using recursion as the only repetition mechanism), but this does work:

     public static IEnumerable<string> DivisibleByThree(string input){ if (input.Length > 1) { foreach(var item in DivisibleByThree(input.Substring(0, input.Length-1))) { yield return item; } } while(input.Length > 0) { if ( SumOfDigits(input) % 3 == 0) yield return input; input = input.Substring(1); }}

     But that's the boring recursion. From a pure performance standpoint, it still spends a lot of time summing the same sequences of digits. There's a probably a way to use recursion to preserve prior work on each recursive call, and in that way make this run significantly faster.

     That is, rather than start with a big string and check progressively smaller segments, start with the small string and with each check add the sum for the just the additional digit:

     public static IEnumerable<string> DivisibleByThree(string input){ for(int i = input.Length - 1; i>=0; i--) { foreach(var item in DivisibleByThreeR(input.Substring(i, input.Length - i), 0, 0, 0)) yield return item; }}public static IEnumerable<string> DivisibleByThreeR(string input, int startPos, int nextPos, int sum){ sum += input[nextPos] - '0'; if (sum % 3 == 0) yield return input.Substring(startPos, nextPos - startPos + 1); if (++nextPos < input.Length) { foreach (var item in DivisibleByThreeR(input, startPos, nextPos, sum)) yield return item; }}

     I'm not sure this is really any faster. I didn't benchmark or test at all beyond getting the right result. In fact, I suspect the iterators will eat up any improvements over the pure-loop version.

     There's also probably a way to move the loop in the outer method also into the recursive function thereby optimize even further. But it was a nice exercise.

     Here's my final fiddle if anyone else wants to play:

     https://dotnetfiddle.net/dGFWNx

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     2/5

   • C# Count the number of items in a Dictionary where the string value contains a certain string

     Top Answer

     Answered Apr 17, 2015 · 6 votes

     You could use LINQ, that would not be quicker in terms of CPU cycles but more readable:

     int count = dict.Count(kv => kv.Value.Contains("test"));-

     if you want to ignore the case you have to use IndexOf:

     int count = dict.Count(kv => kv.Value.IndexOf("test",StringComparison.InvariantCultureIgnoreCase) >= 0);

     You could also use dict.Values.Count(...). Using the dictionary as source collection has just the advantage that you have the key and the value if you need both.

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     3/5

   • c# Lookup for a value in Dictionary of Dictionary

     Top Answer

     Answered Jul 12, 2011 · 4 votes

     you could just have a separate lookup for users:

     Dictionary<string, InfoObject> userLookup;-

     This only of course if you want to optimize for lookup speed, the downside is that addition and removal you have to do now on two separate data structures which have to keep in sync.

     Check all answers on Stack Overflow

     4/5

   • c# :A dictionary of string and list inside a dictionary of string and dictionary

     Top Answer

     Answered Nov 22, 2018 · 2 votes

     The short answer, you are trying to use an overload of a method that does not exist.

     The Add method on a the Dictionary<T1, T2> class does not support passing in a KeyValuePair<T1, T2> directly. The only pattern available via the Add method is Add(T1 key, T2 value);.

     You need to change this line: subdicdic.Add(new KeyValuePair<string, List<string>>("ll", p)); to subdicdic.Add("ll", p);

     I should note that you will experience the exact same issue on the very next line and will need to make a similar adjustment.

     For your reference, I have created a working .NET Fiddle example of this problem.

     Check all answers on Stack Overflow

     5/5

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2. stackoverflow.com › questions › 4233536C# Store functions in a Dictionary - Stack Overflow

   stackoverflow.com › questions › 4233536

   • Cached

   In .NET in order to invoke a function you need to pass all the arguments and if you don't know what the arguments are going to be the only way to achieve this is through reflection. And here's another alternative: class Program. {. static void Main() {. // store. var dico = new Dictionary<int, Delegate>();

   Code sample

   private object function2(object arg1) { return null; }

   private object function3(object arg1, object arg3) { return null; }

   Dictionary<string, Func<State, object>> functions;

   public Interceptor() {

     functions = new Dictionary<string, Func<State, object>>();...

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3. josipmisko.com › posts › c-sharp-dictionaryC# Dictionary: Complete Guide [2023] – Josip Miskovic

   josipmisko.com › posts › c-sharp-dictionary

   • Cached

   • C# Dictionary Example
   • Duplicate Values
   • Iterate Over A Dictionary
   • Get Keys and Values
   • Internals
   • Use Immutable Objects For Keys
   • TryGetValue vs Containskey+Item
   • Dictionary Exceptions
   • Dictionary vs OrderedDictionary
   • Dictionary vs SortedDictionary

   Initialization

   To initialize a dictionary in C#, we first need to provide the type for the key and the type for the value. For example, for a dictionary that stores the name and age of a person, the initialization would be: The first type inside the angle brackets is the key type. The second type is the value type.

   Initial values

   To define initial values at the time of initialization, we use the following syntax: The collection-initializersyntax above is like the initialization of an array. Another way to initialize a dictionary is object initializerintroduced in C# 6:

   Add item to a dictionary

   To add an item to a dictionary, we use the Add method. For example: This would add "Adam" and his age of 24 to the nameToAge dictionary.

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   In C#, a dictionary can only have one value for a key. If we add another value with the same key, then we'll get the KeyNotFoundExceptionexception. For example, if we try to add a value with key "Adam" then we would get: Here we get the exception because there is already a key "Adam" and the dictionary cannot have two values for the same key. As de...

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   To iterate over keys and values of a dictionary, we can use the foreach loop: The item variable is an object of type KeyValuePair which has the properties to provide the key and value. KeyValuePair is a very simple struct. It only holds two properties - Key and Value:

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   Dictionary exposes two read-only properties to get all keys or values: These properties are useful if we want to iterate over all keys or values of a dictionary.

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   C# dictionary uses a hash table as its internal data structure. Hash tables rely on hash codes to locate an item. For example, adding an item to a dictionary performs these 3 steps in the background: 1. Compute a hash code for the key. 2. Verify the key's hash code is not equal to the key already in the dictionary. 3. Place the entry in the hash ta...

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   A dictionary can break if we use a reference type as a key. That's because Dictionary stores a reference to that object and not the object itself. So if we change the object after adding it to the dictionary, then we would break the whole dictionary. Because of that, it's a best practice to use immutable objects, like strings, when using the dictio...

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   TryGetValue and ContainsKey are the two most popular ways of getting a value from a dictionary. For ContainsKey, it's a two-step process: 1. Do the lookup to verify the key exists in the dictionary. 2. Do the lookup to get the value from the dictionary based on the key. On the other hand, TryGetValue does the lookup and gets the value in one step. ...

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   These are the most common exceptions we can get from a dictionary: To prevent these exceptions, use TryGetValue and TryAdd.

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   The main difference between Dictionary and OrderedDictionary is that Dictionary does not guaranteethe order in which it will return values, but OrderedDictionary does. OrderedDictionary is less efficient than Dictionary because insert/delete operations have to be done on an array, with the complexity of O(n) at worst.

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   SortedDictionary is another class that implements IDictionary. The main difference between a Dictionary and SortedDictionary is that SortedDictionary uses a binary search tree with O(log n) retrieval, while Dictionary is a hash table of O(1) complexity for access. Use SortedDictionary if you have an extensive list of items and need them sorted.

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4. People also ask

   How do I create a dictionary of strings using IDictionary?

   • using System.Collections.Generic; public class Example public static void Main() // Create a new dictionary of strings, with string keys, // and access it through the IDictionary generic interface. IDictionary openWith = new Dictionary (); // Add some elements to the dictionary.

   IDictionary Interface (System.Collections.Generic)

   learn.microsoft.com/en-us/dotnet/api/system.collections.generic.idictionary-2?view=net-8.0

   See all results for this question

   What is a dictionary in C#?

   • In this tutorial we learn about a complex data container in C# that stores elements by key/value pairing, called dictionaries. We cover how to define and initialize a dictionary, access and modify dictionary elements with the indexer or loops, remove elements as well as how to check if an item exists in a dictionary.

   C# Dictionary Generic Collection Tutorial | KoderHQ

   www.koderhq.com/tutorial/csharp/dictionary/

   See all results for this question

   How to retrieve a value from a dictionary in C#?

   • To retrieve a value from a dictionary in C#, you can use the TryGetValue method or the indexer. The TryGetValue method is a safe way to get a value from a dictionary without having to handle exceptions. It returns a bool value to let us know if the key was found. For example, we can use TryGetValue this way:

   C# Dictionary: Complete Guide [2023] - Josip Miskovic

   josipmisko.com/posts/c-sharp-dictionary

   See all results for this question

   How to use dictionaries in C#?

   • In the same way, a C# dictionary has a collection of keys and values, where the key is the word, and the value is its meaning. Dictionaries are defined in the System.Collections.Generic namespace, so before we can use them, we must specify the namespace at the top of the document. Now dictionaries will be available to use for use.

   C# Dictionary Generic Collection Tutorial | KoderHQ

   www.koderhq.com/tutorial/csharp/dictionary/

   See all results for this question

5. zetcode.com › csharp › dictionaryC# Dictionary - working with a Dictionary collection in C#

   zetcode.com › csharp › dictionary

   • Cached

   Jul 5, 2023 · We add two new pairs to the dictionary using dictionary access notation and the Add method. Console.WriteLine(string.Join(", ", users)); We use the string Join method to display all elements in one shot. users.Remove("Jane Doe"); A pair is removed with the Remove method. The parameter is the dictionary key.

6. learn.microsoft.com › en-us › dotnetIDictionary<TKey,TValue> Interface (System.Collections ...

   learn.microsoft.com › en-us › dotnet

   • Cached

   Remarks. The IDictionary<TKey,TValue> interface is the base interface for generic collections of key/value pairs. Each element is a key/value pair stored in a KeyValuePair<TKey,TValue> object. Each pair must have a unique key. Implementations can vary in whether they allow key to be null.

7. www.koderhq.com › tutorial › csharpC# Dictionary Generic Collection Tutorial | KoderHQ

   www.koderhq.com › tutorial › csharp

   • Cached

   C# Dictionary Generic Collection Tutorial. In this tutorial we learn about a complex data container in C# that stores elements by key/value pairing, called dictionaries. We cover how to define and initialize a dictionary, access and modify dictionary elements with the indexer or loops, remove elements as well as how to check if an item exists ...

8. makolyte.com › csharp-get-value-from-dictionaryC# - Get value from dictionary | MAKOLYTE

   makolyte.com › csharp-get-value-from-dictionary

   • Cached

   Sep 14, 2023 · Dictionaries store key/value pairs. When you want to get the value for a key, you can use the indexer syntax and specify the key, like this: using System.Collections.Generic; var dictionary = new Dictionary< string, int >() { ["Bob"] = 1, ["Linda"] = 2}; //Get value by key with indexer var val = dictionary["Bob"]; Console.WriteLine($"Bob= {val} "); Code language: C# (cs)

9. www.techiedelight.com › convert-a-dictionary-to-aConvert a Dictionary to a String in C# | Techie Delight

   www.techiedelight.com › convert-a-dictionary-to-a

   • Cached

   Mar 31, 2022 · This post will discuss how to convert a Dictionary<TKey,TValue> to a string in C#. 1. Using String.Join() method. The String.Join () method from the System.Linq namespace is commonly used to concatenate elements of the specified sequence using the specified separator. You can use the Select () method as a helper while joining each key-value ...