screen_variables: Screen variable before penalized regression
Description
Expands a contingency table to a data frame where each observation in the table becomes a single observation in the data frame with corresponding information for each for each combination of the table dimensions.
Usage
screen_variables(x, y, lambda = 0.1, method = c("global-strong", "global-DPP"))
Arguments
x
A table or matrix
y
A vector of outcomes
lambda
a vector of positive values used for the penalization parameter.
method
a string giving the method used for screening. Two possibilities are "global-strong" and "global-DPP"
Value
A list with three elements: lambda which contains the lambda values, selected which contains the indices of the selected variables, and method a string listing the method used.
Details
Note that no standardization is done (not necessary?)
References
Hastie, Tibshirani and Wainwright (2015). "Statistical Learning with Sparsity". CRC Press.