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# adapted from head() and tail()
# 3/10/2017: S. Weisberg modified to add an argument 'cols'
# cols = num will display only the first num cols
some <- function(x, ...) UseMethod("some")
some.default <- function(x, n=10, ...){
len <- length(x)
ans <- x[sort(sample(len, min(n, len)))]
if (length(dim(x)) == 1)
array(ans, n, list(names(ans)))
else ans
}
some.matrix <- function(x, n=10, cols=NULL, ...){
nr <- nrow(x)
nc <- ncol(x)
cols <- if(is.null(cols)) 1:nc else cols
x[sort(sample(nr, min(n, nr))), cols, drop = FALSE]
}
some.data.frame <- function(x, n=10, cols=NULL, ...){
nr <- nrow(x)
nc <- ncol(x)
cols <- if(is.null(cols)) 1:nc else cols
x[sort(sample(nr, min(n, nr))), cols, drop=FALSE]
}
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