I'm new to R and survival analysis, and I am interested to export into a dataframe the results from survfit where there is strata. 

This site has provided an excellent solution but not to one with strata (<https://stat.ethz.ch/pipermail/r-help/2014-October/422348.html>). How can i append (or stack) each strata with an extra column which contains the strata type.
solution in the link offered is not applicable to strata groupings

```
library(survival)
data(lung)
mod <- with(lung, survfit(Surv(time, status)~ 1))
res <- summary(mod)
str(res)

# Extract the columns you want
cols <- lapply(c(2:6, 8:10) , function(x) res[x])
# Combine the columns into a data frame
tbl <- do.call(data.frame, cols)
str(tbl)

```

Thank you in advanced,
R newbie