A lambda is an expression that acts as an anonymous function. Use this tag if you would like to discuss the appropriateness of a lambda or anonymous function in your code.
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Optimise async functions with nested callbacks while using retry pattern [on hold]
I am currently reading some really annoying code. It's basically some weird asynchronous functions with nested lambda/callbacks, and there are some retry pattern involved too. Although I can ...
5
votes
2answers
525 views
Ordering data by boolean
I have a bit of EF Lambda code which returns a list of data from the db table, then orders by a field called IsDefault
At first, the code was
...
0
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0answers
30 views
Node AWS lambda with pg-promise
I've written a lambda to perform simple steps to a redshift database. It runs multiple queries with transaction. I use pg-promise.
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3
votes
1answer
51 views
Numerical streams example
I am reading "Java 8 In Action" (by Raoul-Gabriel Urma, Mario Fusco and Alan Mycroft), section 5.6.3, pages 116 and 117. The code that is presented handles calculating so-called "Pythagorean Triples". ...
6
votes
2answers
141 views
Accessing properties by name with compile-time typesafety
I've recently answered a question here, where the goal is to mimic some functions from System.Reflection in order to avoid it's direct usage as much as possible, ...
2
votes
0answers
64 views
unordered_multimap approach to adjacency list and graph search
I'm looking for suggestions on how to improve the usage of modern C++ features with this simple graph search algorithm, particularly with regard to the use of STL containers and lambda expressions.
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3
votes
0answers
48 views
Generic Factory using Function library
Here's my implementation of Generic Factory using Function library.
It was created using Function library because I understand that the newInstance method is ...
12
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1answer
569 views
Creating a pipeline operator in Java
I wrote the following as more of an experiment than anything else, but I thought it would be fun to share and maybe get some feedback!
Motivation: I started looking at some functional languages and ...
1
vote
1answer
60 views
Template binary heap with lambda function comparator C++
This heap will be used for A* search pathfinding in my 2D isometric game engine. It uses lambda functions (instead of std::less or ...
5
votes
2answers
69 views
Increment all values in a Map by 1
What's the neatest way to increment all values in a HashMap by 1? The map is <String, Integer>, but the key doesn't matter ...
3
votes
2answers
74 views
Plotting a 2D iso-probability curve
I have a library function that returns a pair of two numbers like this
def library_function(x0, x1):
return x0**2 + x1**2, 10*x0*x1 + 1
(Actually, it is a ...
2
votes
4answers
188 views
-1
votes
1answer
34 views
Filled data structure with unique objects that does not have same member variables [closed]
I have in-house template like QList which creates a list of all objects of, say, Book.
This list contains many objects of <...
0
votes
1answer
44 views
ConditionalActions through std::function Lambdas
So I just experimented with some code to make a huge if-else construct more human readable, extendable and configurable (switch positions of conditions).
The idea was to have a vector that contains ...
0
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1answer
71 views
Lambda expression to check even numbers
I wrote this code to check the even numbers from the List. After finding even number I twice the even numbers with the help of <...
1
vote
1answer
77 views
Java Stream - Collections - remove duplicates based on string and presence/absence of local date value
I have a list of objects with a string (name) and a local date (date of deletion).
I wish to implement uniqueness on these objects based on:
If two objects have the same name, then I wish the one ...
3
votes
1answer
48 views
Memory allocation tracking using anonymous lambda wrapper
I had this idea to exploit anonymous lambdas that are immediately executed that wrap around an allocation function to track those allocations in a statically created Stats object.
This is the code I ...
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vote
0answers
34 views
Producer Consumer With Multiple Dependents
I put together a ProducerConsumer class that wraps the C#'s BlockingCollection class with some bells and whistles (producers can have multiple consumers, consumers can have lambdas, built in parallel ...
3
votes
1answer
75 views
Church Numerals
Here is exercise 2.6 from SICP:
Exercise 2.6: In case representing pairs as procedures wasn’t
mind-boggling enough, consider that, in a language that can manipulate
procedures, we can get by ...
4
votes
1answer
53 views
Lambda to obtain a new merged object
The requirement is to iterate over a list of Foos, and when 2 Foos have the same id merge ...
4
votes
1answer
67 views
Credit card / IMEI check digit in Kotlin
I recently had the need to implement Luhn's Algorithm in a Java/Kotlin application. I needed a function that would add the check digit to the string of a number like a credit card or IMEI. It could be ...
2
votes
1answer
66 views
Finding vowels, digits, whitespaces and consonants
I am creating a simple app to find vowels, digits, whitespaces and consonants. the basic idea is to practice multi-threading and writing readable code.
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6
votes
1answer
44 views
Count how many times a value is referenced in a grid
I've got list of points: List<Point> seedPoints. Each Point contains x and ...
1
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1answer
43 views
What is the best way to extract method?
The code snippet is what I want to do. Previously I use a different version of my code. But it is out of joint according to Python coding guidelines because I was assigned my lambda function to a ...
0
votes
2answers
135 views
Validating input values in C#
I began studying C# 5.0 a few days ago and am trying to avoid duplicated code for validation of input values.
...
3
votes
2answers
638 views
Calculate GS1 / SSCC / UPC check digit
I try to write a function which calculates the check digit for shipping label based on the algorithm provided by GS1
http://www.gs1.org/how-calculate-check-digit-manually
Version 1: my first try
<...
1
vote
2answers
22 views
advfind() template
This code basically allows you to provide a collection and a lambda and have the lambda operate on each value iterated even allowing modification of the data if you wish.
I would like to be able to ...
1
vote
1answer
751 views
Python Pandas Apply with a Lambda Function
I have a table in pandas that has two columns, QuarterHourDimID and StartDateDimID ; these columns give me an ID for each date / ...
4
votes
2answers
77 views
Custom key class for .NET 3.5 framework
I use .NET 3.5 framework, so no tuples. I have many use cases where I have to create a custom key for a dictionary. How can I make this better?
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3
votes
2answers
168 views
Most efficient dict filter on key tuple?
I have a dict wherein a value needs to be retrievable by any one of several keys. It seemed that making multiple dictionaries or multiple entries in a single ...
2
votes
1answer
96 views
Return most recent DateTime C# Entity Framework
Job -> Many Quotes
Quote -> EmailLogList
EmailLogList -> Many EmailLogs
I want to return a CreatedDate from an EmailLog which has been created most ...
4
votes
1answer
362 views
(C++14) Handling state in C-style function pointer callbacks
I'm having some issues coming up with a sensible solution for using shared state in a C-style function pointer. I am using GLFW to handle my OpenGL context and have created a thin wrapper around all ...
5
votes
2answers
984 views
Custom sorting of dates
I have implemented a class which implements a list of my custom DateObj. I have sorted the list in a peculiar manner based on the current month. I achieved my ...
3
votes
1answer
65 views
Updating all members of a struct in database
This function is part of our company's project code.
The following function updates six members of struct CpGSMTimeDelayQuery -- ...
2
votes
1answer
73 views
Writing strings to the screen over time
The following methods just write strings to the screen over time to make it look like a typing effect, instead of all at once. The only difference is the argument in the ...
1
vote
1answer
108 views
JavaFX await implementation
I'm debating trying to take a crack at getting something similar to C#'s async-co-routine like nature over on JavaFX.
This is technically feasible since the Quantem toolkit exposes the ...
4
votes
1answer
55 views
Write Once Use Everywhere: Multidimensional array traversal
I have a structure that is organized much like a Sudoku board, where individual cells reside in an n x n region, and those regions reside in an n x n area. I need to be able to address both the ...
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vote
2answers
197 views
Read a txt file and split into 2 csvs based on regex
So I have been told that my code is not good and needs refactoring. I'm struggling to see what I need to do. How do I specify the success and failure conditions for lambda? Also don't get what the ...
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1answer
39 views
Use an optionally passed-in block without repeating yourself
I need to open and read several files for a project. Some of them are plain text files, and I just want a standard File.open to read from. One of them is an XML ...
3
votes
4answers
2k views
Checking whether a list is sorted, ascending or descending
What is the best way to conditionally use an operator? All 3 methods seemed acceptable to me, and the last 2 better.
If you're curious: I've got a list which is unsorted, and many other lists which ...
1
vote
1answer
478 views
Lambda to collect properties in a child object
I have a class:
public class ProductInvoice {
//Some other properties.
private List<ProductEntry> productEntries = newArrayList();
//otherMethods
}
...
5
votes
3answers
423 views
Filtering units by a dynamic Lambda expression
I have a simple if statement which, based on user input, determines which expression is going to be utilized. It looks like it can be done better.
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2
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1answer
322 views
Routing Java objects using conditional consumers
As per a previous question here and answers I got, I used it to get a new implementation. I found that I have to make two implementations match once "to ignore other consumers after matching once" and ...
12
votes
1answer
250 views
Mandelbrot Streams
A recent Mandelbrot question (Hi @EBrown) in C# inspired me to build my own using the Java 8 parallel streams to implement the parallelism that's useful for computing each pixel value.
The intention ...
4
votes
2answers
211 views
Function for timing executions (inspired by MATLAB tic toc)
Inspired by MATLAB's tic/toc I've written a short helper function for calculating execution time.
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10
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2answers
2k views
Return lambda expression based on parameters
This function returns a lambda expression based on the parameters sent. I am sure there is a better way to do this.
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5
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3answers
625 views
Duplicate words in a text
Here is a simplified implementation to obtain the duplicate words in a text using lambda expressions.
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4
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1answer
2k views
Event-listener implementation
While writing a C++ GUI application more or less from scratch I needed some form of an event-listener system, preferably using lambdas. An event should be able to have multiple listeners and the user ...
2
votes
1answer
147 views
Sort files by the type of file
I need to sort files by the type of the File. To accomplish the task I first wrote the code below:
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11
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6answers
3k views
