Using a Javascript for loop to store results in a nested array

Question

Using a Javascript for loop to store results in a nested array

Is there a way to effectively extract specific data from a nested array and place it into a new nested array without just pushing all the data into one array?

var selection = [0,1,3,4];
var allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']]
var selectedProductData = []

for(var apd=0; apd<allProductData.length; apd++) {
  for(var spd=0; spd<allProductData[apd].length; spd++) {
    for(var s=0; s<selection.length; s++) {
      if(allProductData[apd].indexOf(allProductData[apd][spd]) === selection[s]) {
        selectedProductData.push(allProductData[apd][spd])
      }
    }
  }
}
console.log(selectedProductData)

The current output:

[
  "Item1Sku","Item1Name","Item1Price","Item1Available",
  "Item2Sku","Item2Name","Item2Price","Item2Available",
  "Item3Sku","Item3Name","Item3Price","Item3Available"
]

I am aiming for:

[
  ["Item1Sku","Item1Name","Item1Price","Item1Available"],
  ["Item2Sku","Item2Name","Item2Price","Item2Available"],
  ["Item3Sku","Item3Name","Item3Price","Item3Available"]
]

If you have any advice on how to achieve this desired result, I would greatly appreciate it.

javascript arrays loops for-loop

Answer 1

Answer №1

You have the option to associate the data with the values located at a specific index of your choosing.

const
    selection = [0, 1, 3, 4],
    allProductData = [['Item1Sku', 'Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku', 'Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku', 'Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']],
    selectedProductData = allProductData.map(values => selection.map(i => values[i]));

console.log(selectedProductData);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

You have the option to associate the data with the values located at a specific index of your choosing.

const
    selection = [0, 1, 3, 4],
    allProductData = [['Item1Sku', 'Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku', 'Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku', 'Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']],
    selectedProductData = allProductData.map(values => selection.map(i => values[i]));

console.log(selectedProductData);

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 3

Answer №2

Implement Array.prototype.reduce to condense the array and verify if the index of each current element falls within the specified selection array; if yes, include it in the new array.

const selection = [0, 1, 3, 4];
const allProductData = [
  ['Item1Sku', 'Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'],
  ['Item2Sku', 'Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'],
  ['Item3Sku', 'Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']
];

const selectedProductData = allProductData.reduce((acc, curr) => {
  const filtered = curr.filter((product, idx) => selection.includes(idx));

  if (filtered.length) {
    acc.push(filtered);
  }
  return acc;
}, []);

console.log(selectedProductData);

Answer 4

Implement Array.prototype.reduce to condense the array and verify if the index of each current element falls within the specified selection array; if yes, include it in the new array.

const selection = [0, 1, 3, 4];
const allProductData = [
  ['Item1Sku', 'Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'],
  ['Item2Sku', 'Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'],
  ['Item3Sku', 'Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']
];

const selectedProductData = allProductData.reduce((acc, curr) => {
  const filtered = curr.filter((product, idx) => selection.includes(idx));

  if (filtered.length) {
    acc.push(filtered);
  }
  return acc;
}, []);

console.log(selectedProductData);

Answer 5

Answer №3

Consider using the for...of loop instead of i=0;i<x;i++ for better readability and smoother flow in your code.

You can also access each element's index within the initial loop without creating a separate selection array. This way, you can optimize your code by eliminating an extra loop.

var allProductData = [['Item1Sku', 'Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'],['Item2Sku', 'Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'],['Item3Sku', 'Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']];
var selectedProductData = [];

for (let data of allProductData) {
  selectedProductData.push([data[0], data[1], data[3], data[4]]);
}

console.log(selectedProductData)

Answer 6

Consider using the for...of loop instead of i=0;i<x;i++ for better readability and smoother flow in your code.

You can also access each element's index within the initial loop without creating a separate selection array. This way, you can optimize your code by eliminating an extra loop.

var allProductData = [['Item1Sku', 'Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'],['Item2Sku', 'Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'],['Item3Sku', 'Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']];
var selectedProductData = [];

for (let data of allProductData) {
  selectedProductData.push([data[0], data[1], data[3], data[4]]);
}

console.log(selectedProductData)

Answer 7

Answer №4

One efficient approach is to create a new array within the main for loop and append the desired results into that array first, then push the newly created array into the final result array:

var selection = [0,1,3,4];
var allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']]
var selectedProductData = []

for(var apd=0; apd<allProductData.length; apd++) {
  var temp = []; // initialize a new array here
  for(var spd=0; spd<allProductData[apd].length; spd++) {
    for(var s=0; s<selection.length; s++) {
      if(allProductData[apd].indexOf(allProductData[apd][spd]) === selection[s]) {
        temp.push(allProductData[apd][spd]); // store the matching element 
      }
    }
  }
  selectedProductData.push(temp); // add the temporary array into the final result array
}
console.log(selectedProductData)

Answer 8

One efficient approach is to create a new array within the main for loop and append the desired results into that array first, then push the newly created array into the final result array:

var selection = [0,1,3,4];
var allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']]
var selectedProductData = []

for(var apd=0; apd<allProductData.length; apd++) {
  var temp = []; // initialize a new array here
  for(var spd=0; spd<allProductData[apd].length; spd++) {
    for(var s=0; s<selection.length; s++) {
      if(allProductData[apd].indexOf(allProductData[apd][spd]) === selection[s]) {
        temp.push(allProductData[apd][spd]); // store the matching element 
      }
    }
  }
  selectedProductData.push(temp); // add the temporary array into the final result array
}
console.log(selectedProductData)

Answer 9

Answer №5

Implement array.map and array.filter to achieve the desired outcome.

var selection = [0,1,3,4];
var allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']];

let result = allProductData.map(data => {
    return data.filter((el, ind) => selection.indexOf(ind)!=-1);
})

console.log(result);

Answer 10

Implement array.map and array.filter to achieve the desired outcome.

var selection = [0,1,3,4];
var allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Price', 'Item3Available', 'Item3Margin']];

let result = allProductData.map(data => {
    return data.filter((el, ind) => selection.indexOf(ind)!=-1);
})

console.log(result);

Answer 11

Answer №6

Here is a code snippet that accomplishes the desired task. You can also check out the following resources:

let selection = [0,1,3,4];
let allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Ite...
console.log(filtered);

In the comments, there was discussion about the syntax below, specifically regarding the necessity for the callback function in filter() to return true. According to the official documentation from MDN:

The function should act as a predicate to evaluate each element of the array, returning true to keep the element and false otherwise.

let selection = [0,1,3,4];
let allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3P...
console.log(filtered);

The above snippet could be revised as follows.

let selection = [0,1,3,4];
let allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Pr...
console.log(filtered);

There are additional examples provided that achieve the same outcome without errors. In all scenarios, what is returned by .filter() is logically true and meets the conditions specified in the callback function.

let selection = [0,1,3,4];
let allProductData = [[true,true, false, true, false, true], [true,true,true,true,true,true], [false,false,false,false,false,false]];
let filtered = allProductData.map(item =>
  item.filter((val,index) => selection.includes(index) && index > 3)
);
console.log(filtered);
filtered.forEach((item) => item.forEach((val) => console.log(typeof(val))));

Notice the variations in output based on the input values.

let selection = [0,1,3,4];
let allProductData = [[1,2,3,4,5,6], [6,5,4,3,2,1], [8,8,8,8,0,8]];
let filtered = allProductData.map(item =>
  item.filter((val,index) => selection.includes(index) && index > 3)
);
console.log(filtered);
filtered.forEach((item) => item.forEach((val) => console.log(typeof(val))));

Consider the impact of using different types of values, such as null.

let selection = [0,1,3,4];
let allProductData = [[null,null,null,null,null,null], [null,null,null,null,null,null], [null,null,null,null,null,null]];
let filtered = allProductData.map(item =>
  item.filter((val,index) => selection.includes(index) && index > 3)
);
console.log(filtered);
filtered.forEach((item) => item.forEach((val) => console.log(typeof(val))));

Answer 12

Here is a code snippet that accomplishes the desired task. You can also check out the following resources:

let selection = [0,1,3,4];
let allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Ite...
console.log(filtered);

In the comments, there was discussion about the syntax below, specifically regarding the necessity for the callback function in filter() to return true. According to the official documentation from MDN:

The function should act as a predicate to evaluate each element of the array, returning true to keep the element and false otherwise.

let selection = [0,1,3,4];
let allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3P...
console.log(filtered);

The above snippet could be revised as follows.

let selection = [0,1,3,4];
let allProductData = [['Item1Sku','Item1Name', 'Item1Desc', 'Item1Price', 'Item1Available', 'Item1Margin'], ['Item2Sku','Item2Name', 'Item2Desc', 'Item2Price', 'Item2Available', 'Item2Margin'], ['Item3Sku','Item3Name', 'Item3Desc', 'Item3Pr...
console.log(filtered);

There are additional examples provided that achieve the same outcome without errors. In all scenarios, what is returned by .filter() is logically true and meets the conditions specified in the callback function.

let selection = [0,1,3,4];
let allProductData = [[true,true, false, true, false, true], [true,true,true,true,true,true], [false,false,false,false,false,false]];
let filtered = allProductData.map(item =>
  item.filter((val,index) => selection.includes(index) && index > 3)
);
console.log(filtered);
filtered.forEach((item) => item.forEach((val) => console.log(typeof(val))));

Notice the variations in output based on the input values.

let selection = [0,1,3,4];
let allProductData = [[1,2,3,4,5,6], [6,5,4,3,2,1], [8,8,8,8,0,8]];
let filtered = allProductData.map(item =>
  item.filter((val,index) => selection.includes(index) && index > 3)
);
console.log(filtered);
filtered.forEach((item) => item.forEach((val) => console.log(typeof(val))));

Consider the impact of using different types of values, such as null.

let selection = [0,1,3,4];
let allProductData = [[null,null,null,null,null,null], [null,null,null,null,null,null], [null,null,null,null,null,null]];
let filtered = allProductData.map(item =>
  item.filter((val,index) => selection.includes(index) && index > 3)
);
console.log(filtered);
filtered.forEach((item) => item.forEach((val) => console.log(typeof(val))));

Using a Javascript for loop to store results in a nested array

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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