I think I'm having a brain fart, because I can't figure out a simple formula to be able sort a sequence of number into specific order so it can be printed 2 numbers per sheet of paper (one number on one half and second number on second half), so when the printed stack of paper cut in half, separating the numbers, and then these halves put together, the numbers would be in sequence.
So, let's say I have 5 numbers: 3,4,5,6,7, the expected result would be 3,6,4,7,5 or 0,1,2,3,4,5,6,7 would become 0,4,1,5,2,6,3,7 My thought process is:
Obviously, I'm missing a step or two here, or there is a simple mathematical formula for this and hopefully someone could nudge me in a right direction.
This is what I have so far, it doesn't work properly if start number set to 1 or 3
function show()
{
console.clear();
for(let i = 0, count = end.value - start.value, half = Math.round(count/2); i <= count; i++)
{
let result = Math.round((+start.value + i) / 2);
if (i && i % 2)
result = result + half -1;
console.log(i, "result:", result);
}
}
//ignore below
for(let i = 0; i < 16; i++)
{
const o = document.createElement("option");
o.value = i;
o.label = i;
start.add(o);
end.add(o.cloneNode(true));
}
start.value = 0;
end.value = 7;
function change(el)
{
if (+start.value > +end.value)
{
if (el === start)
end.value = start.value;
else
start.value = end.value;
}
}
<select id="start" oninput="change(this)"></select> -
<select id="end" oninput="change(this)"></select>
<button onclick="show()">print</button>
P.S. Sorry, about the title, couldn't come up with anything better to summarize this.
You could get the value form the index
function order(array) {
return array.map((_, i, a) => a[(i % 2 * a.length + i) >> 1]);
}
console.log(...order([3, 4, 5, 6, 7]));
console.log(...order([0, 1, 2, 3, 4, 5, 6, 7]));