get.var {mgcv} | R Documentation |
This routine takes a text string and a data frame or list. It first sees if the
string is the name of a variable in the data frame/ list. If it is then the value of this variable is returned.
Otherwise the routine tries to evaluate the expression within the data.frame/list (but nowhere else) and if
successful returns the result. If neither step works then NULL
is returned. The routine is useful for
processing gam formulae.
get.var(txt,data)
txt |
a text string which is either the name of a variable in data or when
parsed is an expression that can be evaluated in data . It can also be neither in which case the
function returns NULL . |
data |
A data frame or list. |
The evaluated variable, or NULL
Simon N. Wood simon.wood@r-project.org
http://www.stats.gla.ac.uk/~simon/
y <- 1:4;dat<-data.frame(x=5:10) get.var("x",dat) get.var("y",dat) get.var("x==6",dat)