v		input view
cols		column map

Colmap returns a view with columns cols from v in the specified order.

set v [view {A B C} def {1 2 3 4 5 6}]

view $v colmap {C B}

	C	B
0	3	2
1	6	5

view $v colmap {A A}

	A	A
0	1	1
1	4	4

view $v colmap {}

0
1