I have the only array:
[0, 1, 2, 3, 4, 5, 6, 7, 8]
The "first half" of array's data is [0,1,2,3,4] and the second is [5,6,7,8].
Now I should get something like this (it is not random mixing)
[0, 5, 1, 6, 2, 7, 3, 8, 4]
This is an array of data for two columns. I should place first half of data in first column, and the second one in second column.
I'm trying to find a simple solution... Thanks for advice!
You can split your array in half using Math.ceil to round up number and then loop first part and add each element from second part incrementing counter by 2.
var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8], c = 1
var half = arr.splice(Math.ceil(arr.length / 2))
half.forEach(e => (arr.splice(c, 0, e), c += 2))
console.log(arr)
Try the following, using map and an inline if statement
var array = [0,1,2,3,4,5,6,7,8]
var result = array.map(function(item,index){
return (index%2 == 0) ? array[index/2] : array[Math.floor((index+array.length)/2)];
});
console.log(result);
index>>1 not index/2 here. Your note is valid for python2, for example, but JS will give you a float.
You could calculate the index and map the value from the array.
(i >> 1) + ((i & 1) * ((a.length + 1) >> 1)) ^^^^^^^^ take the half integer value ^^^^^^ check for odd ^^^^^^^^^^^^ adjust length ^^^^^^^^^^^^^^^^^^^^ the half value of adjusted length
var array = [0, 1, 2, 3, 4, 5, 6, 7, 8],
result = array.map((_, i, a) => a[(i >> 1) + ((i & 1) * ((a.length + 1) >> 1))]);
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }