row.extractor: Extract min/median/max/quantile Rows from a 'data.frame'

In mrdwab/mrdwabmisc: Miscellaneous R functions, mostly for data processing

Description

The row.extractor function takes a data.frame and extracts rows with the min, median, or max values of a given variable, or extracts rows with specific quantiles of a given variable.

Usage

row.extractor(data, extract.by, what = "all")

Arguments

data	The source data.frame.
extract.by	The column which will be used as the reference for extraction; can be specified either by the column number or the variable name.
what	Options are "min" (for all rows matching the minimum value), "median" (for the median row or rows), "max" (for all rows matching the maximum value), or "all" (for min, median, and max); alternatively, a numeric vector can be specified with the desired quantiles, for instance c(0, .25, .5, .75, 1).

Author(s)

Ananda Mahto

References

• which.quantile function by cbeleites: http://stackoverflow.com/users/755257/cbeleites

• See: http://stackoverflow.com/q/10256503/1270695

See Also

min, max, median, which.min, which.max, quantile

Examples

# Make up some data
set.seed(1)
dat = data.frame(V1 = 1:50, V2 = rnorm(50),
           V3 = round(abs(rnorm(50)), digits=2),
           V4 = sample(1:30, 50, replace=TRUE))
# Get a sumary of the data
summary(dat)

# Get the rows corresponding to the 'min', 'median', and 'max' of 'V4'
row.extractor(dat, 4)

# Get the 'min' rows only, referenced by the variable name
row.extractor(dat, "V4", "min")

# Get the 'median' rows only. Notice that there are two rows
#    since we have an even number of cases and true median
#    is the mean of the two central sorted values
row.extractor(dat, "V4", "median")

# Get the rows corresponding to the deciles of 'V3'
row.extractor(dat, "V3", seq(0.1, 1, 0.1))

mrdwab/mrdwabmisc documentation built on May 23, 2019, 7:15 a.m.