transform {base}
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.
Values
The modified value of _data.
Note
Prior to R 2.3.0, the first argument was named x, but this caused trouble if people wanted to create a variable of that name. Names starting with an underscore are syntactically invalid, so the current choice should be less problematic.
If some of the values are not vectors of the appropriate length, you deserve whatever you get!
See Also
within for a more flexible approach, subset, list, data.frame
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)
Documentation reproduced from R 2.15.3. License: GPL-2.