In R,there is built-in data,for example,the "cars" data which contains two columns,one is "speed",and the other one is "dist".When in Sage,how can I access the speed and dist data?r.cars("speed") alter an error "Unknown environment "table" ",so,is there any solution?
The current way to do this is
r('cars').subset(select='"speed"')
or
r.subset('cars', select='"speed"')
You need to use double quotes for strings when passing them into the interface. Otherwise, speed will be treated as an "identifier" rather than a string. Additionally,
r('cars')['"speed"']
also works.
the following in sage notebook gives you access to cars data
%r
cars
This is not an answer, but a place to aggregate information in the hopes of providing a solution in the future. Obviously Shashank's answer is ideal for anyone interested in just using R straight-up, and several questions on the right will help deal with going between the percent cells and regular cells.
According to the R Help archive, the types of R commands that give you this are
cars[,"speed"]
cars$speed
cars[["speed"]]
subset(cars, select = speed)
I'm not sure whether our interface supports the first three types of access to a data structure. At any rate I don't know where it would.
But more troubling is that I can't get the last one to work without something silly like
sage: r.new("subset(cars,select=speed)")
See this new Trac ticket for more details; I at least view this as a bug.
Here is more documentation for rpy2, which is what is eventually used to interface with R through the rvariable: http://rpy.sourceforge.net/rpy2/doc-2...
That is incorrect. We have our own custom pexpect interface. See http://hg.sagemath.org/sage-main/file/c239be1054e0/sage/interfaces/r.py
Asked: 2012-05-13 14:30:18 +0100
Seen: 600 times
Last updated: May 17 '12
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See also http://ask.sagemath.org/question/1420/r-through-sage-giving-errors-error-object-sage3