[R] Combinations

baptiste auguie baptiste.auguie at googlemail.com
Mon Dec 14 10:50:48 CET 2009


Hi,

Try this,

apply(expand.grid(letters[1:3], letters[24:26]), 1, paste,collapse="")
[1] "ax" "bx" "cx" "ay" "by" "cy" "az" "bz" "cz"

?expand.grid

HTH,

baptiste

2009/12/14 Amelia Livington <amelia_livington at yahoo.com>:
>
> Dear R helpers,
>
> I am working on the scenario analysis pertaining to various interest rates. In this connection I need to form the various combinations as under :
>
> Suppose I have two sets A = (a, b, c) and B = (x,y,z)
>
> Then I can easily form the cominations as
> (ax, ay, az, bx, by, bz, cx, cy, cz)
>
> However, if I have say 5 variables, then total no of possible combinations will be 3^5 = 243.
> Thus, A = (a,b,c), B = (x, y, z), C = (l, m, n), D = (p,q,r), E = (s, t, u). Then may be my possble combination will start as (a, x, l, p, s), then next combination may be (a, x, l, p, u) and so on. The last combination (243rd in this case) may be (c, z, n, r, u) or something like this.
>
> In R, is there any way to list all these 3^5 = 243 combinations?
>
> Amelia
>
>
>
>        [[alternative HTML version deleted]]
>
>
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