William Hudspeth wrote: > Hello, > > I am trying to use rpy to plot a histogram from data residing inside of > a data.frame: > > Normally, from the R prompt, I would use something like this: > > hist(dust_frame$temp_density_raster) > > The documentation indicates that the R function '$' can be accessed with > something like this: > > r['$'] > > but it is unclear how I would use it in the hist function above.
Really? That sounds funny to me - which bit of the documentation do you mean, maybe it needs improving. > Any help would be greatly appreciated. I am using the R 'sp' and > 'spgrass6' libraries to copy a GRASS GIS raster into R, and am then > trying to use the raster grid values to plot, etc. > > Bill I thought $ was more of a syntax thing than a "function", but anyway... I'm guessing you want to access the "temp_density_raster" sub-property of the dataframe "dust_frame" by doing: hist(dust_frame$temp_density_raster) When a dataframe is converted by rpy into a python object, you should get a dictionary where one of the keys should be "temp_density_raster". i.e. try dust_frame["temp_density_raster"] in python. import rpy ... rpy.r.hist(dust_frame['temp_density_raster']) However, a word of warning, if you need to pass the dataframe to any R functions, you should read up about rpy's conversion settings... the catch is that the conversion from R dataframe to python dictionary is lossy and therefore one way. Good luck Peter ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ rpy-list mailing list rpy-list@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rpy-list
