Vocabulary
columns

Inputs and outputs

seq	a sequence
col	a non-negative integer
column	a column

Word description
Outputs a new virtual sequence which presents a fixed column of a matrix represented as a sequence of rows.The ith element of a column is the nth element of the ith element of seq. Every element of seq must be a sequence, and all sequences must have equal length.

Examples

USING: arrays prettyprint columns ; { { 1 2 3 } { 4 5 6 } { 7 8 9 } } 0 <column> >array .
{ 1 4 7 }

Notes
In the same sense that <reversed> is a virtual variant of reverse, <column> is a virtual variant of swap [ nth ] curry map.

Definition

USING: kernel ;

IN: columns

: <column> ( seq col -- column ) \ column boa ; inline