To find Index of Multidimensional Array in Javascript

Question

I have created a multidimensional array in JavaScript and I want to find the exact index of specific value. That value will be user input.

var array = [];
var k = 0;
for (var i = 0; i < 10; i++) {
  array[i] = [];
  for (var j = 0; j < 100; j++) {
    k = k + 1
    array[i].push(k);
  }
}
var index = array.indexOf(`**"What to insert here???"**`);

Answer 1

JSFiddle

/**
 * Index of Multidimensional Array
 * @param arr {!Array} - the input array
 * @param k {object} - the value to search
 * @return {Array} 
 */
function getIndexOfK(arr, k) {
  for (var i = 0; i < arr.length; i++) {
    var index = arr[i].indexOf(k);
    if (index > -1) {
      return [i, index];
    }
  }
}

// Generate Sample Data
var k = 0;
var array = [];
for (var i = 0; i < 10; i++) {
  array[i] = [];
  for (var j = 0; j < 100; j++) {
    k = k + 1;
    array[i].push(k);
  }
}
var needle = 130;
var result = getIndexOfK(array, needle);
console.log('The value #' + needle + ' is located at array[' + result[0] + '][' + result[1] + '].');

Answer 2

this example seems to work well also with IRREGULAR multidimentional array:

function findIndex(valueToSearch, theArray, currentIndex) {
    if (currentIndex == undefined) currentIndex = '';
        if(Array.isArray(theArray)) {
            for (var i = 0; i < theArray.length; i++) {
                if(Array.isArray(theArray[i])) {
                    newIndex = findIndex(valueToSearch, theArray[i], currentIndex + i + ',');
                    if (newIndex) return newIndex;
               } else if (theArray[i] == valueToSearch) {
                   return currentIndex + i;
               }
            }
    } else if (theArray == valueToSearch) {
        return currentIndex + i;
    }
    return false;
}

var a = new Array();
a[0] = new Array(1, 2, 3, 4, 5);
a[1] = 'ciao';
a[2] = new Array(new Array(6,7),new Array(8,9),10);

var specificIndex = findIndex('10', a);

i wrote this speedly so everyone is invited to improve this function!

p.s. now the function returns a STRING value with all indexes separated by comma, you can simply edit it to returns an object

Answer 3

On jsfiddle

function indexOf2d(arr, val) {
    var index = [-1, -1];

    if (!Array.isArray(arr)) {
        return index;
    }

    arr.some(function (sub, posX) {
        if (!Array.isArray(sub)) {
            return false;
        }

        var posY = sub.indexOf(val);

        if (posY !== -1) {
            index[0] = posX;
            index[1] = posY;
            return true;
        }

        return false;
    });

    return index;
}

console.log(indexOf2d(array, 50));

Answer 4

My code does like a PROCV in MS Excel... and identifies the Index searching only in the first column. Maybe help you (or others).

var convertToRoman = function (valueLimitTen) {   
  var convertTable = [  [1, "I"],
                        [2, "II"],
                        [3, "III"],
                        [4, "IV"],
                        [5, "V"],
                        [6, "VI"],
                        [7, "VII"],
                        [8, "VIII"],
                        [9, "IV"],
                        [10, "X"],
                      ];

  var myIndex;  
  for(var i in convertTable){
    if(convertTable[i][0] == valueLimitTen){
      myIndex = i;      
      return convertTable[i][1];      
    }  
  }  
}

console.log(convertToRoman(2)); //Result II
console.log(convertToRoman(10)); //Result X

Answer 5

ES6 has made this considerably easier.

function findIndexOfNestedArray(nestedArray, searchArray) {
  return searchArray.findIndex(item => {
    return item.length === nestedArray.length
    && item.every((a, i) => a === nestedArray[i])
  })
}

Answer 6

Copy and paste this code

Replace <masterArray> with your main array (the one nesting all others)

code:

//Remove Duplicates
  let stringArray = masterArray.map(item=>item.join('')); // transform all nested arrays into strings (for comparation)
  let nonDuplicated = [] // temporary array to compare data
  stringArray.forEach(nestedArrayString=>{
    let reapeatedIndex = nonDuplicated.indexOf(nestedArrayString); // this is the comparator
    if(reapeatedIndex>0){
      indexToRemove = stringArray.indexOf(nestedArrayString);
      console.log('---indexToRemove',indexToRemove)
      stringArray.splice(indexToRemove,1);
      masterArray.splice(indexToRemove,1);
    }else{nonDuplicated.push(nestedArrayString)}
  });
  //
  let lastString = stringArray.filter(foundString=>foundString===stringArray[stringArray.length-1])
  if(lastString.length>1){
    stringArray.splice(stringArray.length-1,1)
    masterArray.splice(masterArray.length-1,1)
  };
    console.log('>> masterArray',masterArray)

i have been searching for a solution to remove arrays inside arrays and came with this ugly but productive solution: works with array of array (twice), but no further nor deeper nesting.

this code will transform the nested arrays into strings => record one by one into a temporary array => compare each time it records if the currently recording string is already inside the array .then if is repeated, remove from masterArray(yours) and stringArray the element

Answer 7

There's a very simple way:

[1,2] === [1,2] // > false
JSON.stringify([1,2]) === JSON.stringify([1,2]) // > true

So we could do something like:

arrays.findIndex(array => JSON.stringify(array)  === JSON.stringify(arrayToCompare))