str2formula {cwhmisc}R Documentation

Extract sides of a formula to strings, Convert back to a formula

Description

str2formula is the inverse function to formula2string. term.names2formula combines two vectors of strings into a formula. formula2string Returns the left and the right hand sides of a formula.

formula2term.names Returns one chosen side of a formula.

formula2Rterm.names Returns the right hand side of a formula.

Usage

  str2formula(s)
  term.names2formula(ls,rs)
  formula2string(form)
  formula2term.names(form,side)
  formula2Rterm.names(form)

Arguments

s A list(left,right) containing the string representation of the left and the right hand side of the formula (one string each).
ls A character vector (usually of length 1) containing the names of the terms on the left hand side of the formula.
rs A character vector containing the names of the terms on the right hand side of the formula.
form a formula.
side one of "left","right".

Value

str2formula: A formula. formula2string: Character vector containing the string representation of the formulas side(s).

Note

The inverse function to str2formula is formula2string.
The inverse functions to term.names2formula are formula2term.names and formula2Rterm.names.
Functions use strsplit

Author(s)

Christian W. Hoffmann <c-w.hoffmann@sunrise.ch>
http://www.wsl.ch/personal_homepages/hoffmann/index_EN

Examples

fo <- a ~ b + c
abc <- formula2string(fo)  #  $left: "a"   $right: "b+c"
str2formula(abc)    # a ~ b + c
term.names2formula(formula2term.names(fo,"left"),c(formula2Rterm.names(fo),"X"))  # a ~ b + c + X
formula2string(a ~ b + c)  #  $left: "a"   $right: "b+c"
formula2string(~ b + c)    #  $left: ""    $right: "b+c"
formula2string(a ~ .)      #  $left: "a"   $right: "."
formula2term.names(a ~ b1 + c,"left")  #   "a"
formula2Rterm.names(a ~ b1 + c)        #   "b1" "c"

[Package cwhmisc version 2.0.1 Index]