:- use_module( library(mtx) ).

%% mtx_column_kv( +Mtx, +ColumnId, -KVs ).
%
%  Create KV pairs of the form NthColumnValue-Row where N is the position of ColumnId.
%  KVs do not include the header KV.
%
%==
% ?- mtx_data( mtcars, Mt ), mtx_column_kv( Mt, mpg, KVs ).
% KVs = [21.0-row(21.0, 6.0, 160.0, 110.0, 3.9, 2.62, 16.46, 0.0, 1.0, 4.0, 4.0), 21.0-row(21.0, 6.0, 160.0, 110.0, 3.9, 2.875, 17.02, 0.0, 1.0, 4.0, 4.0), 22.8-row(22.8, 4.0, 108.0, 93.0, 3.85, 2.32, 18.61, 1.0, 1.0, 4.0, 1.0), 21.4-row(21.4, 6...)|...]
%==
%
% @author nicos angelopoulos
% @version  0.2 2014/8/7,  this was csv_kvs_column_row( CId, Csv, KVs )
%
mtx_column_kv( MtxIn, Column, KVs ) :-
	mtx_header_body( MtxIn, Hdr, Rows ),
	mtx_header_column_pos( Hdr, Column, N ),
	findall( Nth-Row, (member(Row,Rows),arg(N,Row,Nth)), KVs ).