Category "lambda"

coding reduceByKey(lambda) in map does'nt work pySpark

I can't understand why my code isn't working. The last line is the problem: import findspark findspark.init() from pyspark import SparkConf, SparkContext from p

What do the parenthesis following a lambda expression mean?

I am new to Python and I am wondering why this doesn't work for lambda: for person in people: print(lambda person:person.split()[0] + ' ' + person.split()[-

Why does it matter if I use a method reference or a lambda here?

When I try to compile this code import java.util.Optional; public class GenericTest { public static void main(String[] args) { Optional.empty().m

INDIRECT and OFFSET in the function body make a name special

I would like to write a user-defined function CHOOSERANGE that returns a range from 4 coordinates. The first version is as follows: CHOOSERANGE = LAMBDA(row_min

What's the VB.NET equivalent of async delegate in C#?

I'm trying to convert the following extension method (source) from C# to VB: public static Task ForEachAsync<T>(this IEnumerable<T> source,

error: no viable conversion from '(lambda at A.cpp:21:22)' to 'int'

What am I missing? Lambda declaration error. Marked in comment. void solve() { int charCount, time; cin>> charCount >> time; // Generat

Can Python pickle lambda functions?

I have read in a number of threads that Python pickle/cPickle cannot pickle lambda functions. However the following code works, using Python 2.7.6: import cPic

Define a lambda function with infinite number of arguments

Some Excel native functions like VSTACK permit of infinite number of arguments, and they have an intellisense as follows: I would like to know how to define su

Recursive LAMBDA to replace characters by specific substitutes from a lookup table

The goal is to iterate through rows of the character table and replace each character with it's substitute. The character table in this example is ={"&","&a

What is the purpose of std::function, and how to use it?

It is necessary to me to use std::function but I don't know what the following syntax means. std::function<void()> f_name = []() { FNAME(); }; What is

Is it possible to step through a row of data and sum every n-th cell using a Lambda function?

I have a model that produces an array of values that can be several hundred columns wide. Every 25th column contains a number that I need to add to the total. I

How do I use the new computeIfAbsent function?

I very much want to use Map.computeIfAbsent but it has been too long since lambdas in undergrad. Almost directly from the docs: it gives an example of the ol

Merge Map<String, List<String> Java 8 Stream

I would like to merge two Map with JAVA 8 Stream: Map<String, List<String>> mapGlobal = new HashMap<String, List<String>>(); Map<Str

Do lambda expressions have any use other than saving lines of code?

Do lambda expressions have any use other than saving lines of code? Are there any special features provided by lambdas which solved problems which weren't easy

Use Mockito 2.0.7 to mock lambda expressions

I want to mock a query provided on my repository like this: @Test public void GetByEmailSuccessful() { // setup mocks Mockito.when(this.personRepo.find

Pandas dataframe count values above threshold using groupby - code optimization

I have a large pandas dataframe where I want to count the number of values above a threshold (zero) in each column grouped by the values in one name column. Th

python: union keys from multiple dictionary?

I have 5 dictionaries and I want a union of their keys. alldict = [dict1, dict2, dict3, dict4, dict5] I tried allkey = reduce(lambda x, y: set(x.keys()).un

Performance of foreach, array_map with lambda and array_map with static function

What's the performance difference (if there is any) between these three approaches, both used to transform an array to another array? Using foreach Using array

node-lambda - TypeError: handler is not a function

New to AWS and found it quite straightforward so far but really getting stuck packaging a lambda function. I'm using node-lambda to try and run the function bu