| XDataFrame-utils {IRanges} | R Documentation |
Utility functions for manipulating XDataFrame objects.
## S4 method for signature 'expressionORlanguage, ## XDataFrame': eval(expr, envir, enclos = parent.frame())
expr |
The expression, call, or name to be
evaluated. |
envir |
The XDataFrame object in which to evaluate
expr. |
enclos |
The environment in which to look for symbols that
do not exist in the environment formed from
XDataFrame. |
The eval method converts the XDataFrame object
specified in envir to an environmnent, with
enclos as its parent, and then evaluates
expr within that environment. As when evaluating within an
ordinary data.frame, the environment formed from an
XDataFrame contains a symbol for each column name which refers
to the object stored in that column.
The objects are not actually copied into the
environment. Rather, they are dynamically bound using
makeActiveBinding. This prevents unnecessary copying of
the data from the external vectors into R vectors. The values are
cached, so that the data is not copied every time the symbol is
accessed.
The result of expression evaluation.
Michael Lawrence
FilterRules objects, which can be evaluated on a
XDataFrame, and the base eval function.
score <- c(10L, 2L, NA) rd <- XDataFrame(score) eval(quote(score > 3), rd)