How to expand.grid with string elements (the half!)
Perhaps the OP wants the unique combinations of V1 and V2, as in
R> d <- expand.grid(V1=c("x","y","z"),V2=c("x","y","z"))
R> d[ as.numeric(d$V1) <= as.numeric(d$V2), ]
V1 V2
1 x x
4 x y
5 y y
7 x z
8 y z
9 z z
or
R> V <- letters[24:26]
R> rbind(t(combn(V,m=2)), cbind(V,V))
V V
[1,] "x" "y"
[2,] "x" "z"
[3,] "y" "z"
[4,] "x" "x"
[5,] "y" "y"
[6,] "z" "z"
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
Of Rolf Turner
Sent: Monday, June 10, 2013 2:20 AM
To: Gundala Viswanath
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] How to expand.grid with string elements (the half!)
Your question makes no sense at all. The grid expansion
has 9 rows. In case you hadn't noticed, 9 is an odd number
(i.e. not divisible by 2). There are no "halves".
Do not expect the list to read your mind. Instead, ask a
meaningful question.
cheers,
Rolf Turner
On 10/06/13 17:25, Gundala Viswanath wrote:
I have the following result of expand grid:
d <- expand.grid(c("x","y","z"),c("x","y","z"))
What I want is to create a combination of strings but only the half of the all combinations: Var1 Var2 1 x x 2 y x 3 y y 4 z y 5 x z 6 z z What's the way to do it?
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