⚠ Disclaimer
This is a quick example how to calculate the average of different items from different arrays. If there are better solutions, please let me know.
Overview
The data basis are three fruit baskets with different kinds of fruits an the number ot items in the basket. With a React webpage the several baskets can be choosed and the average of the items will be calculated.
const fruitBaskets = [
{
name: "fruitBasket1",
fruitBasket: [
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 3 },
{ fruitName: "Strawberry", count: 9 },
{ fruitName: "Lemon", count: 7 }
]
},
{
name: "fruitBasket2",
fruitBasket: [
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 8 },
{ fruitName: "Lemon", count: 3 }
]
},
{
name: "fruitBasket3",
fruitBasket: [
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 3 },
{ fruitName: "Orange", count: 3 },
{ fruitName: "Lemon", count: 9 },
{ fruitName: "Strawberry", count: 5 }
]
}
];
Implementation
The implementation looks as follows:
The webpage - App.js
The App.js contains the selection of the fruit baskets via a dropdown and a table for the results. The coding is here.
The calculation - data.js
The data.js contains the data of the fruit baskets and the calculation input data. The coding is here.
The calculation has three steps and is described with the baskets 1 and 2 and is in this format.
[
[
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 3 },
{ fruitName: "Strawberry", count: 9 },
{ fruitName: "Lemon", count: 7 }
],
[
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 8 },
{ fruitName: "Lemon", count: 3 }
]
]
merge
Basket 1 and 2 are selected. This two arrays will be merged with this coding.
selectedFruitBaskets.forEach(selectedFruitBasket => {
const found = fruitBaskets.find(
fruitBasket => fruitBasket.name === selectedFruitBasket.name
);
fruits.push(found.fruitBasket);
});
const basketCounts = fruits.length;
const mergedBasket = [].concat(...fruits);
After
[
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 3 },
{ fruitName: "Strawberry", count: 9 },
{ fruitName: "Lemon", count: 7 },
{ fruitName: "Apple", count: 5 },
{ fruitName: "Banana", count: 8 },
{ fruitName: "Lemon", count: 3 }
]
sum
At this step the number of fruits of each kind will be summed
const basketSum = mergedBasket.reduce((acc, curr) => {
if (!acc[curr.fruitName]) {
acc[curr.fruitName] = { ...curr, countInBaskets: 1, sum: curr.count };
return acc;
}
acc[curr.fruitName].countInBaskets += 1;
acc[curr.fruitName].sum += curr.count;
return acc;
}, {});
After
{
"Apple": {
"count": 5,
"countInBaskets": 2,
"fruitName": "Apple",
"sum": 10
},
"Banana": {
"count": 3,
"countInBaskets": 2,
"fruitName": "Banana",
"sum": 11
},
"Lemon": {
"count": 7,
"countInBaskets": 2,
"fruitName": "Lemon",
"sum": 10
},
"Strawberry": {
"count": 9,
"countInBaskets": 1,
"fruitName": "Strawberry",
"sum": 9
}
}
average
After the summation the average can be calulated.
const basketAverage = Object.keys(basketSum).map(fruitName => {
const item = basketSum[fruitName];
return {
fruitName: item.fruitName,
averageCountOverall: item.sum / basketCounts,
averageCountWithMinOne: item.sum / item.countInBaskets,
sum: item.sum
};
});
return basketAverage;
After
[
{
"averageCountOverall": 5,
"averageCountWithMinOne": 5,
"fruitName": "Apple",
"sum": 10
},
{
"averageCountOverall": 5.5,
"averageCountWithMinOne": 5.5,
"fruitName": "Banana",
"sum": 11
},
{
"averageCountOverall": 4.5,
"averageCountWithMinOne": 9,
"fruitName": "Strawberry",
"sum": 9
},
{
"averageCountOverall": 5,
"averageCountWithMinOne": 5,
"fruitName": "Lemon",
"sum": 10
}
]
Result
Coding
See the Coding on GitHub or StackBlitz:
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