Message-ID: <CAM_vjumqnDDG=STEmVLByaQqX1LH3hKk9QaAyyb8xZVza3v-Rw@mail.gmail.com>
Date: 2012-12-05T18:42:01Z
From: Sarah Goslee
Subject: data manipulation between vector and matrix
In-Reply-To: <CAE2FW2m0pnEa6s7aDQL8THVjmLt714KZ+EbMQbv2odnbSemoyQ@mail.gmail.com>
Hi,
On Wed, Dec 5, 2012 at 1:30 PM, C W <tmrsg11 at gmail.com> wrote:
> Dear list,
> I was curious how to subtract a vector from matrix?
>
> Say, I have
>
> mat <- matrix(1:40, nrow=20, ncol=2)
>
> x <-c(1,2)
Thanks for the actual reproducible example.
> I want,
>
> x-mat[1,] and x-mat[2,], and so on... Basically, subtract column elements
> of x against column elements in mat.
>
> But x-mat won't do it.
This will (note the modification to get x - mat):
> sweep(-mat, 2, x, "+")
[,1] [,2]
[1,] 0 -19
[2,] -1 -20
[3,] -2 -21
[4,] -3 -22
[5,] -4 -23
etc.
--
Sarah Goslee
http://www.functionaldiversity.org