CODEWITHSUNDEEP
javascriptarrays
Peter Peach
Peter Peach

Reputation: 169

How can I check if sequence of numbers in an array is increasing by one, or more than one?

I have an array of numbers 

let myNumbers = [95, 96, 97, 98, 99, 101, 102, 103, 104];

I need to return 101 because it broke the sequence, it increased by two.

Thanks.

Upvotes: 1

Views: 2699

Answers (5)

Jitendra G2
Jitendra G2

Reputation: 1206

You can use for loop as like below,

function ShowBreak() {

  let myNumbers = [95, 96, 97, 98, 99, 101, 102, 103, 104]

  for (i = 0; i < myNumbers.length - 1; i++) {
    
    var currentNo = myNumbers[i];
    var nextNo = myNumbers[i + 1];

    var differents = nextNo - currentNo;
    if (differents > 1) {
      console.log(nextNo);
      return alert("Sequence break on number " + nextNo + " by increase " + differents);
    }
  }
  return alert('Sequence not breaked.');
}
<input type="button" class="btn btn-lg btn-primary btn-block" onclick="ShowBreak()" value="Show" />

Upvotes: 0

Ivan Burnaev
Ivan Burnaev

Reputation: 2730

You can start your for loop from the 1 to exclude existing checking.

let myNumbers = [95, 96, 97, 98, 99, 101, 102, 103, 104];

const findElement = arr => {
  for(let i = 1; i < arr.length; i++) {
    if (arr[i] - arr[i-1] > 1) {
      return arr[i]
    }
  }

  return false;
}

console.log(findElement(myNumbers))

Upvotes: 1

Callam
Callam

Reputation: 11539

let myNumbers = [95, 96, 97, 98, 99, 101, 102, 103, 104];

function incrementsBy(n, sequence) {
  let lastNumber = sequence[0]
  for(let n of sequence) {
    if(n - lastNumber > 1) return n
    lastNumber = n
  }
  return null
}

console.log(incrementsBy(1, myNumbers))

Upvotes: 0

Nenad Vracar
Nenad Vracar

Reputation: 122155

You could use find method and check if prev element is equal to current element - 1.

let myNumbers = [95, 96, 97, 98, 99, 101, 102, 103, 104];
let result = myNumbers.find((e, i, a) => i != 0 && e - 1 != a[i - 1]);
console.log(result)

Upvotes: 1

Mohammad
Mohammad

Reputation: 21499

Use simple for loop and check value of items.

let myNumbers = [95, 96, 97, 98, 99, 101, 102, 103, 104];
for(var i=0; i<myNumbers.length; i++)
  if (i!=0 && myNumbers[i]>0 && myNumbers[i]-1 != myNumbers[i-1])
    console.log(myNumbers[i]);

Upvotes: 0

Related Questions