extract_predict_survshap {survex}

Extract Local SurvSHAP(t) from Global SurvSHAP(t)

Description

Helper function to extract local SurvSHAP(t) explanation from global one. Can be can be useful for creating SurvSHAP(t) plots for single observations.

Usage

extract_predict_survshap(aggregated_survshap, index)

Arguments

aggregated_survshap

an object of class aggregated_surv_shap containing the computed global SHAP values

index

a numeric value, position of an observation to be extracted in the result of global explanation

Value

An object of classes c("predict_parts_survival", "surv_shap"). It is a list with the element result containing the results of the explanation.

Examples

veteran <- survival::veteran
rsf_ranger <- ranger::ranger(
    survival::Surv(time, status) ~ .,
    data = veteran,
    respect.unordered.factors = TRUE,
    num.trees = 100,
    mtry = 3,
    max.depth = 5
)
rsf_ranger_exp <- explain(
    rsf_ranger,
    data = veteran[, -c(3, 4)],
    y = survival::Surv(veteran$time, veteran$status),
    verbose = FALSE
)

ranger_global_survshap <- model_survshap(
    explainer = rsf_ranger_exp,
    new_observation = veteran[
        c(1:4, 17:20, 110:113, 126:129),
        !colnames(veteran) %in% c("time", "status")
    ]
)

local_survshap_1 <- extract_predict_survshap(ranger_global_survshap, index = 1)
plot(local_survshap_1)