Re: matrix
- To: mathgroup at smc.vnet.net
- Subject: [mg107098] Re: matrix
- From: Ray Koopman <koopman at sfu.ca>
- Date: Tue, 2 Feb 2010 06:54:19 -0500 (EST)
- References: <hk8nkh$8fs$1@smc.vnet.net>
On Feb 2, 12:26 am, Piotr Munik <piotr.mu... at gmail.com> wrote: > I have matrix M and matrix N > for example > M={{*1*,2},{3,4},{*5*,6},{7,8}} > N={{*1*,8},{*5*,0},{9,7}} > (dimension is diffrent) > I need to make new matrixes which include only this rows from matrix M and > matrix N for which firsts elements are the same in both matrix (M and N). > so I need > M1={{1,2},{5,6}} > N1={{1,8},{5,0}} > Elements of matrix are real (not always integer) > Please for help > Peter m = {{1,2},{3,4},{5,6},{7,8}}; n = {{1,8},{5,0},{9,7}}; mn = Alternatives @@ Intersection[ m1 = m[[All,1]], n1 = n[[All,1]] ] m1 = Pick[m,m1,mn] n1 = Pick[n,n1,mn] 1|5 {{1,2},{5,6}} {{1,8},{5,0}}