Use Y Control Key (Ctr l + Y) to collapse column;First select the Columns whichever needs to be collapsed , and then use Control Key with Y. The selected columns will be deleted. If you are deleting the columns,other columns automatically shifts up or to the left.
on ribbon menus do the double click. select row and column by select data then group and outline then select the column to collapse the press control key with c that is collapse if you press ctrl + x means expand. when the group is expand then click anywhere to collapse.