transform {base}

R Documentation

Transform an Object, e.g. a Data Frame

Description

transform is a generic function, which—at least currently—only does anything useful with dataframes. transform.default converts its first argument to a dataframe if possible and calls transform.data.frame.

Usage

transform(x, ...)
transform.default(x, ...)
transform.data.frame(x, ...)

Arguments

x	The object to be transformed
...	Further arguments of the form tag=value

Details

The ... arguments to transform.data.frame are tagged vector expressions, which are evaluated in the dataframe x. The tags are matched against names(x), and for those that match, the value replace the corresponding variable in x, and the others are appended to x.

Value

The modified value of x.

Note

If some of the values are not vectors of the appropriate length, you deserve whatever you get!

Author(s)

Peter Dalgaard

See Also

subset, list, data.frame

Examples

data(airquality)
transform(airquality, Ozone = -Ozone)
transform(airquality, new = -Ozone, Temp = (Temp-32)/1.8)

attach(airquality)
transform(Ozone, logOzone = log(Ozone)) # marginally interesting ...
detach(airquality)

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