Transform an Object, for Example a Data Frame (original) (raw)
| transform {base} | R Documentation |
|---|
Description
transform is a generic function, which—at least currently—only does anything useful with data frames. transform.default converts its first argument to a data frame if possible and calls transform.data.frame.
Usage
transform(`_data`, ...)
Arguments
| _data | 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 data frame_data. The tags are matched against names(_data), and for those that match, the value replace the corresponding variable in_data, and the others are appended to _data.
Value
The modified value of _data.
Warning
This is a convenience function intended for use interactively. For programming it is better to use the standard subsetting arithmetic functions, and in particular the non-standard evaluation of argument transform can have unanticipated consequences.
Note
If some of the values are not vectors of the appropriate length, you deserve whatever you get!
Author(s)
Peter Dalgaard
See Also
[within](../../base/help/within.html) for a more flexible approach,[subset](../../base/help/subset.html),[list](../../base/help/list.html),[data.frame](../../base/help/data.frame.html)
Examples
transform(airquality, Ozone = -Ozone)
transform(airquality, new = -Ozone, Temp = (Temp-32)/1.8)
attach(airquality)
transform(Ozone, logOzone = log(Ozone)) # marginally interesting ...
detach(airquality)
[Package _base_ version 4.6.0 Index]