EvalFunction: Parse and Evaluate an RSurvey Expression
In USGS-R/RSurvey: Geographic Information System Application

Description Usage Arguments Value Author(s) See Also Examples

This function parses and evaluates a character string representation of an RSurvey expression.

1	EvalFunction(txt, cols)

`txt`	character. A string representation of an R function.
`cols`	list. See `ManageVariables`

Returns the result of evaluating the text expression.

J.C. Fisher, U.S. Geological Survey, Idaho Water Science Center

parse, eval

d <- list(x = 1:10, y = 10:1)
Data("data.raw", d)
cols <- list()
cols[[1]] <- list(id = "X", index = 1, fun = "\"X\"")
cols[[2]] <- list(id = "Y", index = 2, fun = "\"Y\"")
EvalFunction("\"Y\"", cols)
EvalFunction("\"X\" + \"Y\"", cols)
EvalFunction("rnorm(12)", cols)