| formula.utilities {statnet.common} | R Documentation |
Functions for Querying, Validating and Extracting from Formulas
A suite of utilities for handling model formulas of the style used in Statnet packages.
append_rhs.formula(object, newterms, keep.onesided = FALSE) append.rhs.formula(object, newterms, keep.onesided = FALSE) filter_rhs.formula(object, f, ...) nonsimp_update.formula(object, new, ..., from.new = FALSE) nonsimp.update.formula(object, new, ..., from.new = FALSE) term.list.formula(rhs, sign = +1) list_summands.call(object) list_rhs.formula(object) eval_lhs.formula(object)
object |
formula object to be updated or evaluated |
newterms |
list of terms (names) to append to the formula, or
a formula whose RHS terms will be used; either may have a "sign"
attribute vector of the same length as the list, giving the sign
of each term ( |
keep.onesided |
if the initial formula is one-sided, keep it whether to keep it one-sided or whether to make the initial formula the new LHS |
f |
a function whose first argument is the term and whose
additional arguments are forwarded from |
... |
Additional arguments. Currently unused. |
new |
new formula to be used in updating |
from.new |
logical or character vector of variable names. controls how environment of formula gets updated. |
rhs, sign |
Arguments to the deprecated |
append_rhs.formula each return an updated formula
object
nonsimp_update.formula each return an
updated formula object
list_summands.call returns a list of unevaluated calls, with an additional numerical vector attribute "sign" with of the same length, giving the corresponding term's sign as +1 or -1.
list_rhs.formula returns a list of formula terms, with an additional numerical vector attribute "sign" with of the same length, giving the corresponding term's sign as +1 or -1.
eval_lhs.formula an object of whatever type the LHS evaluates to.
append_rhs.formula: append_rhs.formula appends a list of terms to the RHS of a
formula. If the formula is one-sided, the RHS becomes the LHS, if
keep.onesided==FALSE (the default).
append.rhs.formula: append.rhs.formula has been renamed to append_rhs.formula.
filter_rhs.formula: filter_rhs.formula filters through the terms in the RHS of a
formula, returning a formula without the terms for which function
f(term, ...) is FALSE. Terms inside another term (e.g.,
parentheses or an operator other than + or -) will be unaffected.
nonsimp_update.formula: nonsimp_update.formula is a reimplementation of
update.formula that does not simplify. Note that the
resulting formula's environment is set as follows. If
from.new==FALSE, it is set to that of object. Otherwise, a new
sub-environment of object, containing, in addition, variables in new listed
in from.new (if a character vector) or all of new (if TRUE).
nonsimp.update.formula: nonsimp.update.formula has been renamed to nonsimp_update.formula.
term.list.formula: term.list.formula is an older version of list_rhs.formula that required the RHS call, rather than the formula itself.
list_summands.call: list_summands.call, given an unevaluated call or expression
containing the sum of one or more terms, returns a list of the
terms being summed, handling + and - operators and
parentheses, and keeping track of whether a term has a plus or a
minus sign.
list_rhs.formula: list_rhs.formula returns a list containing terms in a given
formula, handling + and - operators and parentheses, and
keeping track of whether a term has a plus or a minus sign.
eval_lhs.formula: eval_lhs.formula extracts the LHS of a formula, evaluates it in the formula's environment, and returns the result.
## append_rhs.formula
(f1 <- append_rhs.formula(y~x,list(as.name("z1"),as.name("z2"))))
(f2 <- append_rhs.formula(~y,list(as.name("z"))))
(f3 <- append_rhs.formula(~y+x,structure(list(as.name("z")),sign=-1)))
(f4 <- append_rhs.formula(~y,list(as.name("z")),TRUE))
(f5 <- append_rhs.formula(y~x,~z1-z2))
## filter_rhs.formula
(f1 <- filter_rhs.formula(~a-b+c, `!=`, "a"))
(f2 <- filter_rhs.formula(~-a+b-c, `!=`, "a"))
(f3 <- filter_rhs.formula(~a-b+c, `!=`, "b"))
(f4 <- filter_rhs.formula(~-a+b-c, `!=`, "b"))
(f5 <- filter_rhs.formula(~a-b+c, `!=`, "c"))
(f6 <- filter_rhs.formula(~-a+b-c, `!=`, "c"))
(f7 <- filter_rhs.formula(~c-a+b-c(a),
function(x) (if(is.call(x)) x[[1]] else x)!="c"))
## eval_lhs.formula
(result <- eval_lhs.formula((2+2)~1))
stopifnot(identical(result,4))