with.hyperframe: Evaluate an Expression in Each Row of a Hyperframe
Description
An expression, involving the names of columns in a hyperframe,
is evaluated separately for each row of the hyperframe.
Usage
## S3 method for class 'hyperframe':
with(data, expr, ..., simplify = TRUE, ee = NULL)
Arguments
data
A hyperframe (object of class "hyperframe")
containing data.
expr
An Rlanguage expression to be evaluated.
...
Ignored.
simplify
Logical. If TRUE, the return value
will be simplified to a vector whenever possible.
ee
Alternative form of expr, as an object of class
"expression".
Value
Normally a list of length
$n$ (where $n$ is the number of rows) containing the results
of evaluating the expression for each row.
If simplify=TRUE and each result is a single atomic value,
then the result is a vector or factor
containing the same values.
Details
This function evaluates the expression expr in each row
of the hyperframe data. It is a method for the generic
function with.
The argument expr should be an Rlanguage expression
in which each variable name is either the name of a column in the
hyperframe data, or the name of an object in the global
environment. The argument ee can be used as an alternative
to expr and should be an expression object (of
class "expression").
For each row of data, the expression will be evaluated
so that variables which are column names of data are
interpreted as the entries for those columns in the current row.
For example, if a hyperframe h has columns
called A and B, then with(h, A != B) inspects
each row of data in turn,
tests whether the entries in columns A and B are
equal, and returns the $n$ logical values.