This function preprocesses survival data for a Cox transfer analysis. It performs several steps including extracting the response and covariates from a model frame, standardizing the covariates, ensuring the validity of offsets and grouping, and sorting the data by survival time in descending order.
Value
A list with the following components:
- x
A matrix of standardized covariates.
- time
A vector of survival times, sorted in descending order.
- status
A vector of censoring indicators, corresponding to the sorted survival times.
- group
A factor vector representing the group classification for each sample, sorted by time.
- offset
A numeric vector representing offsets for each sample, sorted by time.
Details
The function first creates a model frame from the provided formula and data,
then extracts the response variable, which should contain the survival time
and censoring status. The covariates are extracted using a model matrix and
standardized using the scale function. The function also checks the
group and offset arguments, assigning default values if they
are not provided. Finally, all components (time, status, covariates, group,
and offset) are sorted in descending order based on the survival time.