How to get row and column from index?

Question

I\'m drawing a HUGE blank here.

Everything I\'ve found is about getting an index from a given row and column, but how do I get a row and a column from an in

Answer 1

Swift 4

typealias ColumnRowType = (column:Int, row:Int)

func indexToColumnRow(index:Int, columns:Int) -> ColumnRowType
{
    let columnIndex = (index % columns)
    let rowIndex = /*floor*/(index / columns)    // we just cast to an `Int`

    return ColumnRowType(columnIndex, rowIndex)
}

Answer 2

In java, with a column offset of 1, this is a way to do it

int offset=1;
column = Math.floorDiv(location-offset , 3)+offset;
row = ( (location-offset) %3 )+offset ;

Answer 3

For a zero-based index, the two operations are:

row    = (int)(index / width)
column = index % width

I'm using % here since I'm a C guy and, though you haven't specified your language, it certainly looks like one of the C-based ones.

If your question does not pertain to C or its brethren, it will be whatever the modulo operator is for your particular environment, the remainder left over when you divide index by width.

If you don't have a modulo operator, you can use:

row    = (int)(index / width)
column = index - (row * width)

Answer 4

Paxdiablo's answer is the right one. If someone needs the reverse process to get index from row and column:

index = (row * width) + column