Ordering Permutation

Usage

order(...)

Arguments

... a sequence of vectors, all of the same length.

Description

order returns a permutation which rearranges its first argument into ascending order, breaking ties by further arguments.

Details

In the case of ties in the first vector, values in the second are used to break the ties. If the values are still tied, values in the later arguments are used to break the tie (see 1st example).

NA values are treated as greater than any other values so that permutations returned by order move NA values to the top end of the array.

See Also

sort and rank.

Examples

(ii <- order(x <- c(1,1,3:1,1:4,3), y <- c(9,9:1), z <-c(2,1:9)))
## 6  5  2  1  7  4 10  8  3  9
rbind(x,y,z)[,ii] # shows the reordering (ties via 2nd & 3rd arg)

## rearrange matched vectors so that the first is in ascending order
x <- c(5:1, 6:8, 12:9)
y <- (x - 5)^2
o <- order(x)
rbind(x[o], y[o])

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