I am seeking to divide an array into multiple arrays, each based on the presence of a specific element from a separate array

Question

I am seeking to divide an array into multiple arrays, each based on the presence of a specific element from a separate array

Is there a way to split an array into multiple arrays based on specific elements from another array?

For example, take the following situation:

var test = ["1","2","3","env","6","7","8","uat","2344","wersdf","sdfs"];
var test2=["env","uat"];

In this case, we would like to create a mapping as follows:

{
env:["6","7","8"],
uat:["2344","wersdf","sdfs"]
}

It is important to note that the elements in test2 and test1 can vary. Additionally, the two values from test2 may not be consecutive in the test array; other items may be interspersed between them.

javascript jquery arrays typescript angular7

Answer 1

Answer №1

You may find Array#Reduce handy

Start by looping through the test2 array and match the index of test
Proceed to use a for loop with the initial value as ind+1. This will target the next delimiter argument
Add the value to an array using acc[b].push()
Detect the next delimiter by using test2.indexOf(test[i]) == -1 in the else condition. At this point, you need to break the statement and begin with the second argument of test2

function mapper(test, test2) {
  return test2.reduce((acc, b) => {
    let ind = test.indexOf(b); //find starting index of delimiter
    if (ind > -1) {
      acc[b] = acc[b] || []; 
      for (var i = ind+1; i < test.length; i++) {
        if (test2.indexOf(test[i]) == -1) { //detect reaching the next delimiter
          acc[b].push(test[i])
        }else{
         break;
        }
      }
    }
    return acc
  }, {})
  
}

var test = ["1", "2", "3", "env", "6", "7", "8", "uat", "2344", "wersdf", "sdfs"];
var test2 = ["env", "uat"];

console.log(mapper(test, test2))

Answer 2

You may find Array#Reduce handy

Start by looping through the test2 array and match the index of test
Proceed to use a for loop with the initial value as ind+1. This will target the next delimiter argument
Add the value to an array using acc[b].push()
Detect the next delimiter by using test2.indexOf(test[i]) == -1 in the else condition. At this point, you need to break the statement and begin with the second argument of test2

function mapper(test, test2) {
  return test2.reduce((acc, b) => {
    let ind = test.indexOf(b); //find starting index of delimiter
    if (ind > -1) {
      acc[b] = acc[b] || []; 
      for (var i = ind+1; i < test.length; i++) {
        if (test2.indexOf(test[i]) == -1) { //detect reaching the next delimiter
          acc[b].push(test[i])
        }else{
         break;
        }
      }
    }
    return acc
  }, {})
  
}

var test = ["1", "2", "3", "env", "6", "7", "8", "uat", "2344", "wersdf", "sdfs"];
var test2 = ["env", "uat"];

console.log(mapper(test, test2))

Answer 3

Answer №2

const items = ["apple", "banana", "orange", "grapes", "kiwi"];
const fruitsToCheck = ["orange", "grapes"];

const indexes = [];

fruitsToCheck.map(fruit => {
  const index = items.indexOf(fruit);
  indexes.push(index);
})

const result = {};
for(let i = 0; i < indexes.length; i++){
  const part = items.slice(indexes[i] + 1, indexes[i+1]);
  result = {...result, [fruitsToCheck[i]]: [ ...part]};
}
console.log("Resulting object is: ", result);

Answer 4

const items = ["apple", "banana", "orange", "grapes", "kiwi"];
const fruitsToCheck = ["orange", "grapes"];

const indexes = [];

fruitsToCheck.map(fruit => {
  const index = items.indexOf(fruit);
  indexes.push(index);
})

const result = {};
for(let i = 0; i < indexes.length; i++){
  const part = items.slice(indexes[i] + 1, indexes[i+1]);
  result = {...result, [fruitsToCheck[i]]: [ ...part]};
}
console.log("Resulting object is: ", result);

I am seeking to divide an array into multiple arrays, each based on the presence of a specific element from a separate array

Answer №1

Answer №2

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