Reduce refers to the operation, where a array of items is reduced to a single value. Use with language tag like [c++], [google-sheets-formula]. Do NOT use alone.
Questions tagged [reduce]
3548 questions
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1 answer
Problems With Reduce Function
I have been trying to create an example problem for testing out the reduce function in javascript. the program it is intended to a single object from a set of input lines.
function generateInputs(){
var inputLines = Math.floor(Math.random() *…
Leviathan_the_Great
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4 answers
Sum array of object of a key is returning NaN for more than 2 items in JavaScript
Following is my array -
const products = [{
id: "1",
quantity: 3
}, {
id: "2",
quantity: 3
}]
console.log(products.reduce((acc, product) => acc.quantity + product.quantity)) // 6 -> Correct
But if array contains more than 2 items it is…
Nesh
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Await async functions to be done in reduce() function
I have a fuction which includes the following:
const newThreads = newItems.reduce( (acc, item) => {
request(item.href, function(error2, response2, html2){
if(!error2) {
const thread = cheerio.load(html2)
const today =…
Getter Jetter
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3 answers
JS (ES6): Reduce array based on object attribute
I have an array like this:
const fruits = [
{ fruit: 'apple', year: 2018 },
{ fruit: 'apple', year: 2018 },
{ fruit: 'banana', year: 2018 },
{ fruit: 'orange', year: 2018 },
{ fruit: 'apple', year: 2017 },
{ fruit:…
Nibor
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1 answer
BackHandler.exitApp() is not closing the services of react-native android app
When I am using BackHandler.exitApp() to close the app and not removing the app from task manager window of the android, when I am again opening the app, it seems before it starts the service init, it start to call service functions.
So as a…
Ankur Sardar
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4 answers
Compose - functional programming
I wanted to create my own implementation of compose
This works
const compose = (...fns) => fns.reduce((f,g) => (...args) => f(g(...args)));
This not
const compose1 = (...fns) => (...args) => fns.reduce((f,g) => f(g(...args)));
.
const multi = a…
Luke
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How do I set multiple path values in jq at once?
I have figured out how to set a value in my JSON file, package.json, using setpath. Can I do this using a pattern?
cat package.json | jq 'setpath(["dependencies", "acme-a"]; "mytagname")'
What I would like to do is use a pattern like the following…
Stewart
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1 answer
Get the existing intersections between multiple object arrays
I have a couple of arrays which have some same ids. What I want to achieve is get the intersections between the arrays in plain javascript, no libraries. If there is a match of Ids and arraypicklist values are not equal between 2 or more arrays I…
Thomas
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5 answers
JavaScript native groupBy reduce
I am using JavaScript native reduce, however I want to slightly change in the grouping to get my desired result.
I have an array as follows:
const people = [
{name: "John", age: 23, city: "Seattle", state: "WA"},
{name: "Mark", age: 25, city:…
Joe Saad
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6 answers
Javascript reduce not working after function?
Not too sure where I've gone wrong here, expecting to factorialize 5 (1*2*3*4*5 = 120) by turning 5 into a string of [1,2,3,4,5] and then using reduce to multiply the string all together. When I run the code, it just gives me [1,2,3,4,5]...
var arr…
daggett
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How to reduce if-condition looping - Swift
I know it sounds crazy, but just curious how I can reduce the if loop iteration for following? I have tried using guard let but stucked at some place.
{
if arenaEventItems == nil || arenaEventItems.count <= 0 {
return
}
…
Priyanka Wadher Mistry
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Reduction of a JavaScript object with numeric keys and float values causes unpredictable behaviour on iOS
Consider the following two objects:
const ReductionMap = {
'10': 10.5,
'1000': 20.5,
}
const initialValues = {
'10': 110,
'1000': 120,
}
Using lodash v4.17.5 (here _), we reduce initialValues to a new object where each values has been…
Alexander Wallin
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1 answer
How to calculate total using Javascript/ TypeScript reduce
I have the following array:
[Title1: 111, Title2: 222, Title3: 333]
This array is generated from a Web Socket Service and I want to accumulate the values using reduce.
I have the following code, but I can't get it to work:
this.liveDataPriceTotal =…
user3004118
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4 answers
Showing maximum value of an object in an array when it as two max values
I have an array from the api response and its objects.I need to find the value which has maximum total and I have display it I'm unable to solve it , when there are two max values of the total.Is there any solution?
myArray[
{time: "2018-12-02",…
Hema Nandagopal
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3 answers
Using reduce on a list of dictionaries of dictionaries
Here is the given list.
Pets = [{'f1': {'dogs': 2, 'cats': 3, 'fish': 1},
'f2': {'dogs': 3, 'cats': 2}},
{'f1': {'dogs': 5, 'cats': 2, 'fish': 3}}]
I need to use the map and reduce function so that I can have a final result of…
TrashMachine139
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