R help - Nov 2009 - How to make a matrix of a number of factors?

I use the following code to generate a matrix of factors. I'm
wondering if there is a way to make it more general so that I can have
any number of factors (not necessarily 5).

a=3
b=4
c=5
d=6
e=7

A=1:a
B=1:b
C=1:c
D=1:d
E=1:e

X=matrix(nr=a*b*c*d*e,nc=5)

for(i_a in 1:a-1) {
  for(i_b in 1:b-1) {
    for(i_c in 1:c-1) {
      for(i_d in 1:d-1) {
        for(i_e in 1:e-1) {
          X[(((i_a * b + i_b) * c + i_c) * d + i_d) * e + i_e + 1, ] c(i_a+1,
i_b+1, i_c+1, i_d+1, i_e+1)
        }
      }
    }
  }
}
print(X)

Hi,

Try this,

do.call(expand.grid, lapply(7:3, seq, from=1))


HTH,

baptiste


2009/11/22 Peng Yu <pengyu.ut at gmail.com>:
> I use the following code to generate a matrix of factors. I'm
> wondering if there is a way to make it more general so that I can have
> any number of factors (not necessarily 5).
>
> a=3
> b=4
> c=5
> d=6
> e=7
>
> A=1:a
> B=1:b
> C=1:c
> D=1:d
> E=1:e
>
> X=matrix(nr=a*b*c*d*e,nc=5)
>
> for(i_a in 1:a-1) {
> ?for(i_b in 1:b-1) {
> ? ?for(i_c in 1:c-1) {
> ? ? ?for(i_d in 1:d-1) {
> ? ? ? ?for(i_e in 1:e-1) {
> ? ? ? ? ?X[(((i_a * b + i_b) * c + i_c) * d + i_d) * e + i_e + 1, ] >
c(i_a+1, i_b+1, i_c+1, i_d+1, i_e+1)
> ? ? ? ?}
> ? ? ?}
> ? ?}
> ?}
> }
> print(X)
>
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