| transform {base} | R Documentation |
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.
transform(`_data`, ...)
_data |
The object to be transformed |
... |
Further arguments of the form |
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.
The modified value of _data.
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!
Peter Dalgaard
within for a more flexible approach,
subset,
list,
data.frame
transform(airquality, Ozone = -Ozone) transform(airquality, new = -Ozone, Temp = (Temp-32)/1.8) attach(airquality) transform(Ozone, logOzone = log(Ozone)) # marginally interesting ... detach(airquality)