maxn {cgwtools}

Functions to find the n-th maximum or minimum of a vector or array.

Description

These functions behave similarly to min, max and which(x == max/min (x) to find the n-th greatest max or min of a dataset.

Usage

maxn(x,nth=1)
minn(x,nth=1)
which.maxn(x, nth = 1, arr.ind = FALSE, useNames = TRUE)
which.minn(x, nth = 1, arr.ind = FALSE, useNames = TRUE) 

Arguments

x

A vector or array of numerical or string values. Note: ordering of string values may not be what is expected. See Details.

nth

Which lesser(greater, for min functions) to find, with default nth==1 being identical to max, min.

arr.ind

Same meaning as for which, a logical value indicating whether to return the array indices if x is an array.

useNames

Same meaning as for which, a logical value indicating if the value of arrayInd() should have (non-null) dimnames at all

Details

Quoting the help page for max : Character versions are sorted lexicographically, and this depends on the collating sequence of the locale in use: the help for Comparison gives details. The max/min of an empty character vector is defined to be character NA. (One could argue that as "" is the smallest character element, the maximum should be "", but there is no obvious candidate for the minimum.)

Value

For maxn, minn, a single value which is the nth- max or min.

For the which.min,max functions, quoting from which: If arr.ind == FALSE (the default), an integer vector, or a double vector if x is a long vector, with length equal to sum(x), i.e., to the number of TRUEs in x. If arr.ind == TRUE and x is an array (has a dim attribute), the result is arrayInd(which(x), dim(x), dimnames(x)), namely a matrix whose rows each are the indices of one element of x

Author(s)

Carl Witthoft, [e-mail]

See Also

which , max

Examples

set.seed(17) # for repeatability
foo <- matrix(sample(1:10,20,replace=TRUE),5,4)
maxn(foo,3)
which.minn(foo,4)