TERR Script to be used in a Spotfire 'Expression Function'0

TERR_Expression_Function_Handling_Input_Columns.r

#######################################################
#
# Expression Functions in Spotfire can take arbitrarily
# many columns as input. Columns will be passed to TERR
# in order as 'input1', 'input2', etc. 
# 
# This shows how to capture an arbitrary number of 
# columns and to put them into a data frame.
#
#######################################################

inputs <- grep("^input[0-9]+$",ls(), value = TRUE)

# capture columns as a matrix
my.matrix <- sapply(inputs, function(x) {eval(parse(text = x))})

# capture columns as a data frame
my.df <- as.data.frame(sapply(inputs, function(x) {eval(parse(text = x))}))


# Now do something with the matrix or dataframe that evaluates 
# to a vector of length equal to the number of rows in the table 
# i.e. length(input1)