This function is a helper function for the package and is not exported.
extractOneGroupOneEvent(model, group = NA, event = NA, firstRow = TRUE)
A survfit object.
Number of the chosen group. If the model-object has only one Strata (Group), this parameter can be NA.
If the model-object is a multistate-model, the event-type needs to be specified, otherwise it can be NA.
Typically, a survfit-model does not include data of time=0, if true this function tries to add a column time=0 as a first row.
Returns a data frame with the times, estimate, upper and lower CI and the n.Risk of one group and one event of a Kaplan Meier estimator or a competitive risk analysis