a 1- or 2- dimensional dataset whose indices corresponding
to
select.spec will be returned.
A 1-dimensional dataset is considered to be a single, unnamed
column of
length() rows.
select.spec
vector of index specifications for
x,
which can be of mode "logical", "numeric", and/or "character".
To specify all rows or columns of
x,
use
"@ALL" or
"";
to specify the last row or column
(plus one if
is.target.index=T)
of
x, use "@END" or "".
For mode "character", ranges (such as
"Weight:Mileage") will be accepted,
so long as both substrings on either side of the
":" are matched.
Expressions that reference a column name of
x
do not need to use subscripting
(e.g., reals > algebra - 2 may be used instead of
testscores[,"reals"] >
testscores[,"algebra"] - 2).
OPTIONAL ARGUMENTS:
which
character value, either "columns" (the default) or "rows",
specifying whether to return indices of the columns
or rows of
x.
row.names
character vector specifying potential matches for
select.spec
if
which="rows".
The default is
name.rows(x).
col.names
character vector specifying potential matches for
select.spec
if
which="columns".
The default is
name.cols(x).
row.count
integer value specifying the index of the last row
of
x.
The default is
count.rows(x).
col.count
integer value specifying the index of the last column
of
x.
The default is
count.cols(x).
is.target.index
logical flag: if
TRUE,
then for each element of
select.spec
which is either "@END" or "",
the corresponding return value will be
row.count
(if
which="rows") or
col.count
(if
which="columns") plus one;
if
FALSE,
the corresponding return value will be
row.count
or
col.count.
Also if
TRUE,
then for each element of
select.spec
which is a character value not matching any
of
row.names
(if
which="rows") or
col.names
(if
which="columns"),
the corresponding return value will be
row.count
or
col.count plus one
and will be given the non-matching name as a name attribute.
return.list
logical flag: if
TRUE,
the return value will be of mode
"list".
VALUE:
(if
return.list=T, a list of) integer vector(s)
the length of the matches in
x
of
select.spec,
and whose values are the index into
x that
is specified by the corresponding matching element
of
select.spec.