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1. Top results related to eight function of dictionary in c# with example python

   • Python's unpack function in C#

     Top Answer

     Answered Dec 20, 2013 · 6 votes

     I think BinaryReader is what you want.

     Something like this would be the equivalent (assuming data is a byte array):

     using (var stream = new MemoryStream(data)) { using (var reader = new BinaryReader(stream)) { stream.Seek(2, SeekOrigin.Begin);- var value1 = reader.ReadInt16(); var value2 = reader.ReadInt16(); }}

     This should skip the first 2 bytes, then load the next 4 bytes into two short variables.

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     1/5

   • Invalid usage of aggregate function Sum() and Type: String while computing the SUM with DATATABLE in C#

     Top Answer

     Answered Oct 01, 2013 · 0 votes

     You cannot compute Sum of a Column with type string. You need to make sure your column has type integer.

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     2/5

   • C# Dictionary equivalent to Python's get() method

     Top Answer

     Answered Dec 09, 2019 · 7 votes

     Here's the correct way to use TryGetValue. Note that you can not set the return value to the default before calling TryGetValue and just return it as TryGetValue will reset it to it's default value if the key is not found.

     public static TValue GetOrDefault<TKey, TValue>( this IDictionary<TKey, TValue> dictionary, TKey key, TValue defaultValue){ TValue value; if(key == null || !dictionary.TryGetValue(key, out value)) return defaultValue; return value;}

     Of course you might actually want an exception if key is null since that is always an invalid key for a dictionary.

     This can now be simplified to the following with C# 7.0 inline out variable declarations.

     return key == null || !dictionary.TryGetValue(key, out var value) ? defaultValue : value;

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     3/5

   • What is the purpose of a zip function (as in Python or C# 4.0)?

     Top Answer

     Answered May 23, 2017 · 14 votes

     Someone actually asked a question here fairly recently that I answered with the Zip extension method, so it's obviously important for some people. ;)

     Actually, it is a fairly important operation for mathematical algorithms - matrices, curve fitting, interpolation, pattern recognition, that sort of thing. Also very important in engineering applications like digital signal processing where much of what you do is combine multiple signals or apply linear transforms to them - both are based on the sample index, hence, zip it. Zipping two sequences is far, far faster than sorting and joining them based on some key, especially when you know in advance that the sequences have the same number of elements and are in the same order.

     I can't get into tight specifics here on account of my current employment, but speaking generally, this is also valuable for telemetry data - industrial, scientific, that sort of thing. Often you'll have time sequences of data coming from hundreds or thousands of points - parallel sources - and you need to aggregate, but horizontally, over devices, not over time. At the end, you want another time sequence, but with the sum or average or some other aggregate of all the individual points.

     It may sound like a simple sort/group/join in SQL Server (for example) but it's actually really hard to do efficiently this way. For one thing, the timestamps may not match exactly, but you don't care about differences of a few milliseconds, so you end up having to generate a surrogate key/row number and group on that - and of course, the surrogate row number is nothing more than the time index which you already had. Zipping is simple, fast, and infinitely parallelizable.

     I don't know if I'd call it foundational, but it it is important. I don't use the Reverse method very often either, but by the same token I'm glad I don't have to keep writing it myself on those rare occasions when I do find a need for it.

     One of the reasons it might not seem that useful to you now is that .NET/C# 3.5 does not have tuples. C# 4 does have tuples, and when you're working with tuples, zipping really is a fundamental operation because ordering is strictly enforced.

     Other Answers

     Answered Mar 12, 2010 · 14 votes

     A use case:

     >>> fields = ["id", "name", "location"]>>> values = ["13", "bill", "redmond"]>>> dict(zip(fields, values)){'location': 'redmond', 'id': '13', 'name': 'bill'}

     Try doing this without zip...

     Other Answers

     Answered Mar 12, 2010 · 13 votes

     zip is useful if you'd like to iterate over multiple iterables simultaneously, which is a reasonably common scenario in Python.

     One real-world scenario where zip has come in handy for me is if you have an M by N array, and you want to look at columns instead of rows. For example:

     >>> five_by_two = ((0, 1), (1, 2), (2, 3), (3, 4), (4, 5))>>> two_by_five = tuple(zip(*five_by_two))>>> two_by_five((0, 1, 2, 3, 4), (1, 2, 3, 4, 5))

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     4/5

   • Python hmac in c#

     Top Answer

     Answered Dec 08, 2021 · 3 votes

     The Python code is wrong. It doesn't decode the BASE64 key but uses it as if it was the actual key. The key must be decoded using the base64 library, not encoded as UTF-8.

     Strings in Python3 are Unicode and the default encoding is utf-8, so there's no need to explicitly specify it.

     The following code returns the same hash as the C# code:

     import base64import hashimport hashlibms = "ninoingfbf"key = "AgQGCAoMDhASFA=="h=hmac.new(base64.b64decode(key),ms.encode(),hashlib.sha256)print (h.hexdigest())

     This returns

     2980906b9e1933357db6fc6b791d2d43564555a949667cc9525eff037466add0

     Which is identical to the C# output

     2980906b9e1933357db6fc6b791d2d43564555a949667cc9525eff037466add0

     .NET 5 added a Convert.ToHexString method, so the C# code becomes:

     using System;using System.Security.Cryptography;using System.Text;var msg = "ninoingfbf";var key = "AgQGCAoMDhASFA==";HMACSHA256 hmac = new(Convert.FromBase64String(key));var h = hmac.ComputeHash(Encoding.UTF8.GetBytes(msg));Console.WriteLine(Convert.ToHexString(h).ToLower());

     If you want to save the hash text for comparison you can get rid of ToLower() and use a case-insensitive comparison. In C# you can use one of the String.Compare overloads that ignores case, eg :

     var areEqual=String.Compare(hash1,hash2,true);

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     5/5

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

   stackoverflow.com › questions › 4233536

   • Cached

   Like this: Dictionary<int, Func<string, bool>>. This allows you to store functions that take a string parameter and return boolean. dico[5] = foo => foo == "Bar"; Or if the function is not anonymous: dico[5] = Foo; where Foo is defined like this: public bool Foo(string bar) {.

   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. stackoverflow.com › questions › 36990860c# - Dictionaries and Functions - Stack Overflow

   stackoverflow.com › questions › 36990860

   • Cached

   May 3, 2016 · Console.WriteLine("Some stuff"); } answered May 2, 2016 at 20:15. Evk. 100k 8 148 197. 3. You can also do lambda expressions: dict.Add("do", () => Console.WriteLine("Some stuff"));. The key here is that Action is a delegate type, and it specifies that the function must take no parameters and return no result.

4. People also ask

   What is Python dictionary get function?

   • Python Dictionary get function is used to return value at a given key position. In this section, we discuss how to use this one, and the syntax behind this Python dictionary get function is: The dict get function returns the value at the specified user key. TIP: Please refer to the Dict in Python.

   Python dictionary get function - Tutorial Gateway

   www.tutorialgateway.org/python-dictionary-get-function/

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   How to use dictionaries with functions?

   • A fine example of using Dictionaries with functions is demonstrated below by making a simple calculator which can compute basic mathematical functions such as addition subtraction, multiplication and division. Depending on User’s choice one can proceed with the earlier calculation or begin with a fresh one.

   Making a Simple Calculator using Dictionaries with Functions ... - Medium

   medium.com/@ayush_dixit/making-a-simple-calculator-using-dictionaries-with-functions-8fc699e141e6

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   What is a dictionary in C#?

   • Dictionary in C# is a collection of keys and values. In a dictionary, the keys are unique. This means that there can be no two elements with the same key. Dictionary in C# can be seen as a hash table or a hash map. It uses the key to access the element in the map. In C#, a Dictionary is defined in the System.Collections.Generic namespace.

   Mastering C# Dictionary: A Comprehensive Guide

   www.gyata.ai/c-sharp/c-sharp-dictionary/

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   Does Python have a built-in Dictionary?

   • Here's an older SO about python's built in dictionary - stackoverflow.com/questions/327311/…. MSDN documentation speaks about average case time complexity (more particularly, they say that the complexity "approaches" the given function), and these are the same as presented in Python documentation.

   Python vs C# dictionaries - Stack Overflow

   stackoverflow.com/questions/23912373/python-vs-c-sharp-dictionaries

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5. www.gyata.ai › c-sharp › c-sharp-dictionaryMastering C# Dictionary: A Comprehensive Guide

   www.gyata.ai › c-sharp › c-sharp-dictionary

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   Dec 8, 2023 · // Accessing elements in a dictionary int value = myDictionary["Apple"]; Console.WriteLine(value); // Outputs 1 Modifying Elements in a Dictionary Modifying elements in a dictionary is as simple as assigning a new value to a key. // Modifying elements in a dictionary myDictionary["Apple"] = 5; Console.WriteLine(myDictionary["Apple"]); // Outputs 5

6. github.com › pythonnet › pythonnetc# <-> python dictionary converter · Issue #623 - GitHub

   github.com › pythonnet › pythonnet

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   Feb 9, 2018 · using (Py.GIL()) { //create a instance of PyConverter var converter = NewMyDictConverter(); var scope = Py.CreateScope(); scope.Exec( "a={'0': 1, '1': [1, \"2\"]}" ); dynamic a = scope.Get("a"); // mock a python dictionary var b = converter.ToClr(a); //Convert python dict to Clr Dictionary<string, object> var c = converter.ToPython(b ...

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

   zetcode.com › csharp › dictionary

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   Jul 5, 2023 · C# Dictionary tutorial shows how to work with a Dictionary collection in C#. A dictionary, also called an associative array, is a collection of unique keys and a collection of values, where each key is associated with one value. Retrieving and adding values is very fast. Dictionaries take more memory because for each value there is also a key.

8. www.linkedin.com › learning › transition-from-cDictionaries - Transition from C# to Python Video Tutorial ...

   www.linkedin.com › learning › transition-from-c

   So in the dictionaries folder, let's open up the C sharp example first. And then similar to the arrays and lists example, we're going to take a look at a C sharp example and then go and...

9. www.tutorialsteacher.com › python › python-dictionaryPython Dictionary (With Examples) - TutorialsTeacher.com

   www.tutorialsteacher.com › python › python-dictionary

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   Dictionaries are optimized to retrieve values when the key is known. The following declares a dictionary object. Example: Dictionary. capitals = {"USA":"Washington D.C.", "France":"Paris", "India":"New Delhi"} print(type(capitals)) #output: <class 'dict'> Try it. Above, capitals is a dictionary object which contains key-value pairs inside { } .