A fork is additional data associated with a filesystem object.On Linux, a resource fork is used to store additional data with a filesystem object. A file always has at least one fork for the data portion, and additional forks may exist.On NTFS, this is analogous to an Alternate Data Stream (ADS), and the default data stream for a file is just called $DATA. Zone.Identifier is commonly used by Windows to track contents downloaded from the Internet. An ADS is typically of the form: C:\path\to\filename.extension:some_fork_name, and some_fork_name is the value that should populate fork_name. filename.extension should populate file.name, and extension should populate file.extension. The full path, file.path, will include the fork name.
Unmodified original url as seen in the event source.Note that in network monitoring, the observed URL may be a full URL, whereas in access logs, the URL is often just represented as a path.This field is meant to represent the URL as it was observed, complete or not.
places the data frame in the search path at position 2, and providedthere are no variables u, v or w in position 1,u, v and w are available as variables from the dataframe in their own right. At this point an assignment such as
does not replace the component u of the data frame, but rathermasks it with another variable u in the working directory atposition 1 on the search path. To make a permanent change to thedata frame itself, the simplest way is to resort once again to the$ notation:
More precisely, this statement detaches from the search path the entitycurrently at position 2. Thus in the present context the variablesu, v and w would be no longer visible, except underthe list notation as lentils$u and so on. Entities at positionsgreater than 2 on the search path can be detached by giving their numberto detach, but it is much safer to always use a name, for exampleby detach(lentils) or detach("lentils")
attach() is a generic function that allows not only directoriesand data frames to be attached to the search path, but other classes ofobject as well. In particular any object of mode "list" may beattached in the same way:
Functions may be recursive, and may themselves define functions withinthemselves. Note, however, that such functions, or indeed variables,are not inherited by called functions in higher evaluation frames asthey would be if they were on the search path.
The important (but technically optional) parameter data =production specifies that any variables needed to construct the modelshould come first from the production data frame.This is the case regardless of whether data frameproduction has been attached on the search path or not.
With a few exceptions, R relies on the underlying OS functions tomanipulate filepaths. Some aspects of this are allowed to depend on theOS, and do, even down to the version of the OS. There are POSIXstandards for how OSes should interpret filepaths and many R usersassume POSIX compliance: but Windows does not claim to be compliant andother OSes may be less than completely compliant.
for any other executable cmd on the path or given by anabsolute filepath: this is useful to have the same environment as Ror the specific commands run under, for example to run ldd orpdflatex. Under Windows cmd can be an executable or abatch file, or if it has extension .sh or .pl theappropriate interpreter (if available) is called to run it.
If there is an argument ending .RData (in any case) it isinterpreted as the path to the workspace to be restored: it implies--restore and sets the working directory to the parent of thenamed file. (This mechanism is used for drag-and-drop and fileassociation with RGui.exe, but also works for Rterm.exe.If the named file does not exist it sets the working directoryif the parent directory exists.)
Under Windows with R CMD you may also specify your own.bat, .exe, .sh or .pl file. It will be rununder the appropriate interpreter (Perl for .pl) with severalenvironment variables set appropriately, including R_HOME,R_OSTYPE, PATH, BSTINPUTS and TEXINPUTS. Forexample, if you already have latex.exe on your path, then
If you do not wish to hardcode the path to Rscript but have itin your path (which is normally the case for an installed R except onWindows, but e.g. macOS users may need to add /usr/local/binto their path), use 2b1af7f3a8