[R] Extract subset of rows

[John Haart]

Hi,

I have two matrices with a common field = species what i want to do is make a matrix that combines the data held in the other two based on the species name.

I.e ( simple example)

Matrix 1 - monocot

SPECIES	V1

A			2
B			3
C			4	
D			5

Matrix 2 - PCAresults

SPECIES	V2

A			0.2
B			0.3
C			4.1	
D			3.2

matrix 3 - What i want

SPECIES	V1	V2

A			2	0.2
B			3	0.3
C			4	4.1
D			5	3.2



my attempt has been this 

test <-monocot[which(monocot$SPECIES%in%PCAresults$SPECIES),] 

But this returns matrix with only those found in each but doesn't "import" the data from PCAresults

Any help would be greatly appreciated

John