Javascript - compare boolean arrays and creating a new one

Question

I'm curious how I could compare these array's, bare in mind this is an example, it's not limited to 4 array's, as this could be more or less depending on user selection)

let array0 = [false,true,false,false,false,false,false,false,true,false,false,false,false,false,false,false,false,false,false,true ,true ,false,false,false,false,false,false,false,false,true ,true ,true ,true,true,false,true,true,true,true,false,false]
let array1 = [true ,true,false,false,false,false,false,false,true,false,false,false,false,false,false,false,false,false,true ,true ,true ,true ,false,true ,false,true ,true ,false,true ,true ,true ,true ,true,true,true ,true,true,true,true,true ,true ]
let array2 = [true ,true,true ,true ,true ,true ,true ,true ,true,true ,true ,true ,true ,true ,true ,true ,true ,false,false,false,false,false,false,false,false,false,false,false,false,false,false,false,true,true,true ,true,true,true,true,true ,true ]
let array3 = [true ,true,true ,true ,true ,true ,true ,true ,true,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true ,true,true,true ,true,true,true,true,true ,true ]

The end goal is to get a new array with a true or false value based on comparison/validation of all of the above array's, a true value should only be set if all 4 array's have a true value in that index position, and a false if of them or not for example:

Array	result	Array	result	Array	result
array0[0]	false	array0[1]	true	array0[2]	false
array1[0]	true	array1[1]	true	array1[2]	false
array2[0]	true	array2[1]	true	array2[2]	true
array3[0]	true	array3[1]	true	array3[2]	false
result	false		true		false

let resultArray = [false, true, false, false, /* etc */]

Hope I have explained this correctly.

Nina Scholz · Accepted Answer · 2022-03-05 18:39:25Z

2

You could transpose the array and map all items having truthy values.

const
    array0 = [false, true, false, true, true],
    array1 = [true, true, false, false, true],
    array2 = [false, true, true, false, true],
    array3 = [true, true, true, true, true],
    transpose = (r, a) => a.map((v, i) => [...(r[i] || []), v]),
    result = [array0, array1, array2, array3]
        .reduce(transpose, [])
        .map(a => a.every(Boolean))

console.log(result);

answered Mar 5, 2022 at 18:39

Nina Scholz

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Comments

Tushar Shahi · Accepted Answer · 2022-03-05 18:27:41Z

I think you should create an array containing all your arrays. Then you will probably need a double for loop to calculate individual values. Check the nth index for every array and compute the value, where i is from 0 to the length of array (Basically, do the check for all the indices). You should get your computed result. Below is using only 2 arrays:

let array0 = [false,true,false,false,false,false,false,false,true,false,false,false,false,false,false,false,false,false,false,true,true,false,false,false,false,false,false,false,false,true,true,true,true,true,false,true,true,true,true,false,false]
let array1 = [true,true,false,false,false,false,false,false,true,false,false,false,false,false,false,false,false,false,true,true,true,true,false,true,false,true,true,false,true,true,true,true,true,true,true,true,true,true,true,true,true]
let newArr = [array0,array1];
let ans = [];

for(let i = 0 ; i < array1.length; i++){
  let val = true;
  for(let j = 0 ;j < newArr.length; j++){
      val = val && newArr[j][i];
      if(!val) break;
  }
ans.push(val);
}
console.log(ans);

Alan Omar · Accepted Answer · 2022-03-05 18:31:02Z

let array0 = [false, true, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, true, true, false, false, false, false, false, false, false, false, true, true, true, true, true, false, true, true, true, true, false, false]
let array1 = [true, true, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, true, true, true, true, false, true, false, true, true, false, true, true, true, true, true, true, true, true, true, true, true, true, true]
let array2 = [true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, true, true, true, true, true, true, true, true]
let array3 = [true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true]

let MAX_INDEX = Math.max(array0.length, array1.length, array2.length, array3.length)

let result = []

for (let i = 0; i < MAX_INDEX; i++) {
  result[i] = array0[i] || false &&
    array1[i] || false &&
    array2[i] || false &&
    array3[i] || false
}

console.log(result)

Peterrabbit · Accepted Answer · 2022-03-05 18:34:09Z

Since all your arrays have same length I guess you could simply do that:

let array0 = [false, true, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, false, true, true, false, false, false, false, false, false, false, false, true, true, true, true, true, false, true, true, true, true, false, false]
let array1 = [true, true, false, false, false, false, false, false, true, false, false, false, false, false, false, false, false, false, true, true, true, true, false, true, false, true, true, false, true, true, true, true, true, true, true, true, true, true, true, true, true]
let array2 = [true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, true, true, true, true, true, true, true, true]
let array3 = [true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true]

let result = Array.from({
  length: array0.length
}).map((_, i) => array0[i] && array1[i] && array2[i] && array3[i])

console.log(result)

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