Subsetting vectors and data frames

Usage

subset(x, ...)
subset.default(x, subset)
subset.data.frame(x, subset, select)

Arguments

x Object to be subsetted
... How to subset, depends on object
subset logical expression
select expression, indicating variables to select from a dataframe

Description

For ordinary vectors, the result is simply x[subset & !is.na(subset)].

For dataframes, the subset argument works similarly on the rows. Note that subset will be evaluated in the dataframe.

The select argument exists only for dataframes. It works by first replacing variable names in the selection expression with the corresponding column numbers in the dataframe and then using the resulting integer vector to index the columns. This allows the use of the standard indexing conventions so that e.g. ranges of variables can be specified easily.

Value

Selected rows and columns of the object x.

Author(s)

Peter Dalgaard

See Also

[, transform

Examples

data(airquality)
subset(airquality, Temp > 80, select = c(Ozone, Temp))
subset(airquality, Day == 1, select = -Temp)
subset(airquality, select = Ozone:Wind)

attach(airquality)
subset(Ozone, Temp > 80)

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