Questions tagged [lambda]
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.
218
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0
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38
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Lazy evaluation vs strict one applied to fib
I have this OCaml problem:
Recall the polymorphic type lazy seen in class, the function delay which transforms a ...
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4
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0
answers
65
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Print columns of text without hard coding the width (attempt 5)
If you'd like to print this:
...
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0
votes
3
answers
215
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Print columns of text without hard coding the width (attempt 4)
If you'd like to print this:
One Two Three Four
1 2 3 4
using this:
...
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0
votes
0
answers
48
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Print columns of text without hard coding the width (attempt 3)
If you'd like to print this:
One Two Three Four
1 2 3 4
using this:
...
- 808
4
votes
1
answer
246
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Print columns of text without hard coding the width (attempt 2)
If you'd like to print this:
One Two Three Four
1 2 3 4
using this:
...
- 808
3
votes
2
answers
205
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2D Matrix in C++
I wanted to play with a two-dimensional generic data container in C++ and explore different methods of traversals: using closures and iterators. I'd like a review of it.
...
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2
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1
answer
159
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Finger Exercise: Update book cipher by creating new book
I'm working my way through the finger exercises in John Guttag's book Introduction to Python Programming, third edition. The following finger exercise on page 143 describes encryption/decryption with ...
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0
votes
1
answer
190
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Compute the goals scored by football teams in their matches in a season, from json data
Please look at the Java Stream methods in the for each loop.
This method totals the score for when the your desired team is playing during the football season - input param teamKey - it is either ...
3
votes
4
answers
138
views
Print sums of pairs from 1 to 10
This takes the sum of pairs of numbers from 1 to 10 and outputs the sum, the original numbers, and some connecting text. Output:
intArray.length 10
{Sum of + 1 and 2 =3, Sum of + 3 and 4 =7, Sum of +...
1
vote
1
answer
63
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Meta Collatz Sequence
Context
Chapter 6 of Learn You A Haskell contains a function called chain, which outputs the Collatz sequence of a given input.
(In short, it takes a natural number....
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votes
1
answer
58
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Class accepting data input by variable, function pointer or lambda
Background
I am writing a library that takes some data from the user and works with it. I was experimenting with ways to allow users to provide the data by the following methods:
As a (global) ...
- 103
0
votes
1
answer
82
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Avoiding Java stream repeated code using lambdas
This is the code for adding addon product to carts. Suppose the cart has a cake so a candle would be an addon. I see this ...
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0
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1
answer
37
views
Is using except TypeError the right way to do this? [closed]
I have some code that uses a lambda to enhance the functionality. For backward compatibility reasons, this lambda can take one or two arguments. To handle these ...
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2
votes
2
answers
122
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Radio with channels
Realize the Radio and Channel classes that represent radio and a radio station. The radio class offers an argumentless constructor and the following methods:
addChannel: stores and returns a new ...
- 23
0
votes
1
answer
76
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Simplify this code that adds string representation of class members to a List [closed]
I have a bunch of code that adds the string representation of members in a class to a List.
...
2
votes
1
answer
379
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=PRINTF("{1} - {2}", ... ) in Excel without VBA - LAMBDA functions with variable number of arguments
The TEXTJOIN function has a really nice interface:
=TEXTJOIN(delimiter, ignore_empty, text1, [text2], …, [text252])
... where ...
- 2,335
7
votes
2
answers
496
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A Hit Counter For AWS Python Lambda powered with DynamoDB
I'm learning how to use DynamoDB and various AWS services, so I decided to write a simple hit counter application for my education of how to use DynamoDB. This application deduplicates hits from the ...
- 875
2
votes
1
answer
286
views
splitting a tuple into N-element tuples
This nice hack should allow you to split a tuple into N-element tuples, thereby effectively splitting a tuple into pairs, triples, ... For example, this allows you to split an input parameter pack, ...
- 1,404
0
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1
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91
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Image pixelwise operation function with multiple inputs in C++
This is a follow-up question for Tests for the operators of image template class in C++ and A recursive_transform template function for the multiple parameters cases in C++. I appreciated G. Sliepen's ...
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3
votes
1
answer
241
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Delete older EBS Volume snapshots except few with certain tags using Python, Lambda
I am learning Python and managed to accomplish the above. But my script doesn't seem optimal. Could someone help to take a review and suggest for betterment?
...
2
votes
1
answer
103
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A recursive_transform template function for the multiple parameters cases in C++
This is a follow-up question for A recursive_transform template function for the binary operation cases in C++. Thanks for G. Sliepen's answer. Based on the mentioned suggestion, I am attempting to ...
- 3,830
1
vote
0
answers
68
views
A recursive_transform template function for the binary operation cases with execution policy in C++
This is a follow-up question for A recursive_transform template function for the binary operation cases in C++, A recursive_transform Template Function with Unwrap Level for Various Type Arbitrary ...
- 3,830
2
votes
1
answer
104
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A recursive_transform template function for the binary operation cases in C++
This is a follow-up question for A recursive_transform Template Function with Unwrap Level for Various Type Arbitrary Nested Iterable Implementation in C++ and A recursive_print Function For Various ...
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1
vote
1
answer
330
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An implementation of Uber's "Fare Estimator" [CodeSignal]
CodeSignal put out a challenge by Uber that involves writing a "fare estimator" that involves a function dependent on cost per minute, cost per mile, ride time and ride distance.
The formula ...
- 101
1
vote
1
answer
608
views
How to make this nested lambda expression readable?
This is the code that joins the list with another one. Also makes use of a static utility to makes use of hashmap for id and name.
I've added null checks to safeguard the code with NPE.
The key ...
- 11
1
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0
answers
37
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Fetch the nearest city, optimised with Redis on a Lambda
I have a lambda function which returns the nearest city from a latitude and longitude.
My algorithm for this is resource heavy and time consuming. To optimise this, I hash the coordinates into a 6 ...
- 111
6
votes
0
answers
185
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Create 'classical' visitor from lambdas
I've watched a talk by Fedor Pikus on design patterns held at CppCon 2019. Motivated by this, I wrote my own visitor implementation and some helpers which allow me to create a visitor from a couple of ...
- 203
0
votes
1
answer
133
views
Correct use of Serializable with lambda functions
I'm practicing saving and reading serializable objects when a friend told me serializable objects have no use in real life, that I'd better focus on JSON or XML to serialize my objects when I came ...
5
votes
1
answer
5k
views
C++ event loop and thread signaling
Use case
This is an event loop and signaling system I created for a piece of software which will have multiple asynchronous server/clients/event-emitters/ui, some of those components will have their ...
- 300
25
votes
4
answers
4k
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Poor man's JIT using nested lambdas
While answering this code review question, I came up with a way to convert an equation given at runtime to a std::function<double(double)> that would evaluate ...
- 44.8k
5
votes
1
answer
978
views
Emplace a lambda which captured a unique_ptr into container like queue
I'd like to emplace a lambda which captured a unique-pointer into a container, but it failed to compile under GCC 7.3.0 as C++17. From the error messages, it's calling the copy constructor of ...
- 51
-1
votes
2
answers
103
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Using a lambda to generically create an arbitrary class wrapper around some object of type T [closed]
While experimenting with some of C++'s language features, I was able to successfully design an invokable nameless function call through the use of a lambda that generically creates an arbitrary class ...
- 965
1
vote
0
answers
109
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A Generic Two Dimensional Data Plane with Common Math Calculation Build-in Methods in C#
This is a follow-up question for A Generic Two Dimensional Data Plane with SubPlane Method in C#. Thanks to aepot's answer.
I am trying to implement a series methods to enhance the ability and ...
- 3,830
0
votes
1
answer
879
views
Is this the right way to do lambda method chaining in python? [closed]
I come from java background and I am trying to implement lambda chaining in Python. Below is my code
...
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1
vote
1
answer
233
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ConvertAll Methods Implementation for Jagged Arrays in C#
This is a follow-up question for ConvertAll Methods Implementation for Multidimensional Array in C# and ConvertAll Methods Implementation for Multidimensional Array in C# - follow-up. Besides the ...
- 3,830
1
vote
1
answer
81
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ConvertAll Methods Implementation for Multidimensional Array in C# - follow-up
This is a follow-up question for ConvertAll Methods Implementation for Multidimensional Array in C#. Thanks to aepot's answer and Olivier's answer. In order to match the usage of the build-in API <...
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9
votes
2
answers
469
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ConvertAll Methods Implementation for Multidimensional Array in C#
I am trying to perform some conversions with multidimensional array in C# and I have checked the discussion ConvertAll and 2-dimensional arrays. I found that ...
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1
vote
0
answers
104
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A Bspline module for AMO
Here is a (reduced version of) a module for Bsplines, which I have used multiple times for my work on Atomic, Molecular, and Optical physics (AMO, in the trade lingo, a.k.a. "I love", in ...
- 302
1
vote
1
answer
87
views
A Function Applier for Applying Various Algorithms on Nested Container Things in C++
This is a follow-up question for A recursive_replace_if Template Function Implementation in C++, A recursive_copy_if Template Function Implementation in C++, A recursive_count_if Function with Unwrap ...
- 3,830
1
vote
0
answers
75
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A recursive_replace_copy_if Template Function Implementation in C++
This is a follow-up question for A recursive_copy_if Template Function Implementation in C++. Besides the recursive version std::ranges::copy_if, I am trying to ...
- 3,830
2
votes
1
answer
60
views
A recursive_copy_if Template Function Implementation in C++
This is a follow-up question for A recursive_transform for std::vector with various return type and A recursive_transform Template Function Implementation with std::invocable concept in C++. Besides ...
- 3,830
1
vote
1
answer
90
views
A recursive_transform Template Function Implementation with recursive_invoke_result_t and std::ranges::transform in C++
This is a follow-up question for A recursive_transform Template Function Implementation with std::invocable concept in C++, A recursive_transform Template Function Implementation with std::invocable ...
- 3,830
4
votes
2
answers
291
views
Nested std::deque and std::vector Type Test Cases for recursive_transform Template Function in C++
This is a follow-up question for A recursive_transform Template Function Implementation with std::invocable concept in C++, A recursive_transform Template Function ...
- 3,830
2
votes
1
answer
96
views
A recursive_transform Template Function Implementation with std::invocable Concept and Execution Policy in C++
This is a follow-up question for A recursive_transform Template Function Implementation with std::invocable concept in C++ and A recursive_transform Template ...
- 3,830
3
votes
1
answer
208
views
A recursive_transform Template Function Implementation with std::invocable concept in C++
This is a follow-up question for A recursive_transform for std::vector with various return type, A recursive_transform Template Function with Execution Policy, A recursive_count_if Template Function ...
- 3,830
4
votes
1
answer
368
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Recursive LAMBDA() function to create a formula that adds internal separators to a string in Excel
I have created a named function with signature PadInternal(base, width, paddingStr) where:
base is a string you want to add ...
- 2,335
2
votes
1
answer
76
views
Building a list from the Catresian square of an array
The code generates a list containing all possible combinations of the items of an array. Every triplet of items contains two operands and the third item containing ...
- 123
2
votes
1
answer
140
views
A recursive_transform Template Function with Execution Policy
This is a follow-up question for A recursive_transform for std::vector with various return type, A recursive_transform Function For Various Type Nested Iterable With std::variant Implementation in C++ ...
- 3,830
2
votes
1
answer
123
views
A ones Function for Boost.MultiArray in C++
This is a follow-up question for An Element-wise Increment and Decrement Operator For Boost.MultiArray in C++ and A recursive_transform Template Function for BoostMultiArray. I am trying to implement ...
- 3,830
3
votes
2
answers
1k
views
Create dummy variables in dataframe using for loop and apply lambda
I like to compute dummy variables based on the existing values in a dataframe and a dictionary with certain "cut off" points. I wonder whether I need to get rid of the for loop in the ...
- 133