Question

I’ve got a sequence of numbers – 1,2,3,4,5,....100

The sequence is divided by groups and every one has 3 numbers in it (except the last one) – [1,2,3] [4,5,6] ... [97,98,99] [100]

I’m trying to find the index of a group for a specific number.

For example:

• Number 1 will have group index 0
• Number 4 will have group index 1
• Number 6 will have group index 1

What’s the fastest way to find that group index, besides looping through all groups?

Thank you.

Answer 1

What you need is:

var groupNo = Math.floor((x-1)/3);