What is the reason for the output being [['a', 'b']], as opposed to [['a','b'],['c','d']]?

Question

What is the reason for the output being [['a', 'b']], as opposed to [['a','b'],['c','d']]?

I've been working on the freecodecamp Bonfire: Chunky Monkey problem and I'm almost there with the solution. However, I'm stuck on why the output is [['a', 'b']], instead of [['a', 'b'], ['c', 'd']]. Can anyone help me figure out what's wrong with my code?

function chunk(arr, size) {
  var array = [];
  var tmp = [];
  for(var i = 0; i < Math.floor(arr.length/size); i++) {
    for(var j = 0; j < size; j++) {
      tmp.push(arr[j]);
    }
    array.push(tmp);
    tmp = [];
    arr.splice(0,size);
  }
  return array;
}
chunk(['a', 'b', 'c', 'd'], 2);

javascript arrays

Answer 1

Answer №1

By modifying the length of arr within the loop, you are causing the outer loop to only execute once. To avoid this issue, it's important to store the original length before making any changes:

function splitArray(arr, size) {
    var result = [];
    var temp = [];

    // Store the original length to prevent looping issues
    var iterations = Math.floor(arr.length / size);

    for (var i = 0; i < iterations; i++) {
        for (var j = 0; j < size; j++) {
            temp.push(arr[j]);
        }
        result.push(temp);
        temp = [];
        arr.splice(0, size);
    }
    return result;
}

Answer 2

By modifying the length of arr within the loop, you are causing the outer loop to only execute once. To avoid this issue, it's important to store the original length before making any changes:

function splitArray(arr, size) {
    var result = [];
    var temp = [];

    // Store the original length to prevent looping issues
    var iterations = Math.floor(arr.length / size);

    for (var i = 0; i < iterations; i++) {
        for (var j = 0; j < size; j++) {
            temp.push(arr[j]);
        }
        result.push(temp);
        temp = [];
        arr.splice(0, size);
    }
    return result;
}

Answer 3

Answer №2

Make sure to be cautious about altering the length of arr during each loop iteration to avoid issues with the loop running multiple times. Additionally, it is best to stick to a single loop for efficiency.

function chunk(arr, size) {
  var array = [];
  for(var i = 0; i < arr.length; i += size) {
    array.push(arr.slice(i, i + size));
  }
  return array;
}
chunk(['a', 'b', 'c', 'd'], 2);

Answer 4

Make sure to be cautious about altering the length of arr during each loop iteration to avoid issues with the loop running multiple times. Additionally, it is best to stick to a single loop for efficiency.

function chunk(arr, size) {
  var array = [];
  for(var i = 0; i < arr.length; i += size) {
    array.push(arr.slice(i, i + size));
  }
  return array;
}
chunk(['a', 'b', 'c', 'd'], 2);

Answer 5

Answer №3

Here is an alternate method:

function divide(arr, size) {
 var array = [];
 var temp = [];
 var index = 0;
 for(var i = 0; i < Math.ceil(arr.length/size); i++)
 {
   for(var j = index; j < index + size; j++)
   {
     arr[j] != undefined?temp.push(arr[j]):false;
   }
   index = index + size;
   array.push(temp);
   temp = [];
  }
 return array;
 }
 console.log(divide(['a', 'b', 'c', 'd', 'e', 'f'], 2));

Note: This method can handle arrays with both even and odd numbers of elements.

Answer 6

Here is an alternate method:

function divide(arr, size) {
 var array = [];
 var temp = [];
 var index = 0;
 for(var i = 0; i < Math.ceil(arr.length/size); i++)
 {
   for(var j = index; j < index + size; j++)
   {
     arr[j] != undefined?temp.push(arr[j]):false;
   }
   index = index + size;
   array.push(temp);
   temp = [];
  }
 return array;
 }
 console.log(divide(['a', 'b', 'c', 'd', 'e', 'f'], 2));

Note: This method can handle arrays with both even and odd numbers of elements.

Answer 7

Answer №4

While many have provided answers with functional codes, my focus is on explaining the reasoning behind it.

At first glance, it may seem like the outer loop would iterate twice, given that Math.floor(arr.length/size) returns a value of 2 initially:

for(var i = 0; i < Math.floor(arr.length/size); i++) {
    // ....
}

However, it's important to note that in the first iteration, the array arr is actually chunked:

arr.splice(0,size); // arr is ['c', 'd'] after this step

When the loop moves to the second iteration, i is now 1 and Math.floor(arr.length/size) evaluates to Math.floor(['c', 'd']/2). This condition results in a failure, causing the loop to exit prematurely. Therefore, contrary to initial expectations, there isn't a second iteration.

Answer 8

While many have provided answers with functional codes, my focus is on explaining the reasoning behind it.

At first glance, it may seem like the outer loop would iterate twice, given that Math.floor(arr.length/size) returns a value of 2 initially:

for(var i = 0; i < Math.floor(arr.length/size); i++) {
    // ....
}

However, it's important to note that in the first iteration, the array arr is actually chunked:

arr.splice(0,size); // arr is ['c', 'd'] after this step

When the loop moves to the second iteration, i is now 1 and Math.floor(arr.length/size) evaluates to Math.floor(['c', 'd']/2). This condition results in a failure, causing the loop to exit prematurely. Therefore, contrary to initial expectations, there isn't a second iteration.

Answer 9

Answer №5

Example of utilizing a loop to configure chunk size.

function createChunks(inputArray, chunkSize) {
  var outputArray = [];

  for (var i = 0, len; i < chunkSize; i++) {
    len = inputArray.length;
    if (len >= chunkSize) {
      outputArray[i] = inputArray.splice(0, chunkSize === 1 ? len : chunkSize);
    } else if (len > 0) {
      outputArray[i] = inputArray.splice(0, len);
    }
  }
  return outputArray;
}

var output = createChunks(['x', 'y', 'z', 'w'], 1);
console.log(output);

Answer 10

Example of utilizing a loop to configure chunk size.

function createChunks(inputArray, chunkSize) {
  var outputArray = [];

  for (var i = 0, len; i < chunkSize; i++) {
    len = inputArray.length;
    if (len >= chunkSize) {
      outputArray[i] = inputArray.splice(0, chunkSize === 1 ? len : chunkSize);
    } else if (len > 0) {
      outputArray[i] = inputArray.splice(0, len);
    }
  }
  return outputArray;
}

var output = createChunks(['x', 'y', 'z', 'w'], 1);
console.log(output);

What is the reason for the output being [['a', 'b']], as opposed to [['a','b'],['c','d']]?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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