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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0answers
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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 ...
11
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1answer
552 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 ...
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vote
1answer
51 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
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2answers
59 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
68 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 ...
-1
votes
1answer
33 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
votes
1answer
63 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
71 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
45 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
30 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
74 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
48 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
60 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 ...
1
vote
1answer
56 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.
...
6
votes
1answer
43 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
vote
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
131 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
525 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
679 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
75 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?
...
3
votes
2answers
144 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
93 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
329 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
849 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
64 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
72 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
106 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 ...
1
vote
2answers
189 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 ...
1
vote
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
1k 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
420 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
393 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.
...
2
votes
1answer
299 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
244 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
183 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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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
610 views
Duplicate words in a text
Here is a simplified implementation to obtain the duplicate words in a text using lambda expressions.
...
4
votes
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
140 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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6answers
3k views
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1answer
309 views
Catch all checked exceptions and turn into unchecked exception
I am currently trying to learn Lambdas and following the book Java SE8 for the really Impatient and just finished Chapter 1 of it. This is the question, I am trying to get done with:
Didn’t you ...
7
votes
1answer
279 views
Proper checked exception handling with lambda functions
I'm having trouble finding a clean way to handle checked exceptions thrown by a lambda function passed as a parameter in Java.
I'm writing a Client which will interact via RMI with a Server to play a ...
0
votes
1answer
66 views
Repetitive code for a projected field in a lambda
I have a simple projection in my code. Taking away the majority of the fields which are not of interest, it looks like the following:
...
5
votes
2answers
5k views
Optimize method to iterate to over Map<String, List<Object>>
I have a Map<String, List<Object>> multiFieldMap and I need to iterate over its value set and add the value to ...
5
votes
1answer
173 views
Multiple functions to establish a fallback value for a property until not null
I have a property (called "Head") that can be set externally. When "Head" is not set, it uses Unity3D's MonoBehaviour functions to try to find the best value for "...
11
votes
2answers
533 views
Printing removed items using lambdas and streams
I'm struggling to make my lambdas readable.
I've seen various approaches. Below are three different examples that all do the same thing.
Forgive the example: I suspect there are better actual ...
2
votes
2answers
164 views
Comparing triangles using Java 8 streams
I'm trying to get more familiar with Java 8 streams as they seem to be very powerful (and shorter), so I rewrote a method to use streams. However I'm not very satisfied with it and would like some ...
