I am reading Hadley's: http://r4ds.had.co.nz/tibbles.html
However, I am still having difficulty referencing a tibble in a tibble.
> library(tidyquant)
> f <- tq_get("F", get="key.ratios")
> f
# A tibble: 7 x 2
            section               data
              <chr>             <list>
1        Financials <tibble [150 x 5]>
2     Profitability <tibble [170 x 5]>
3            Growth <tibble [160 x 5]>
4         Cash Flow  <tibble [50 x 5]>
5  Financial Health <tibble [240 x 5]>
6 Efficiency Ratios  <tibble [80 x 5]>
7  Valuation Ratios  <tibble [40 x 5]>
> f["Financials"]
Error: Column `Financials` not found
> f[["Financials"]]
NULL
> f$Financials
NULL
Warning message:
Unknown or uninitialised column: 'Financials'. 
> f$data[[f$section == 'Financials']]
Error in f$data[[f$section == "Financials"]] : 
  attempt to select less than one element in integerOneIndex
> f$data[[1]]$Financials
NULL
Warning message:
Unknown or uninitialised column: 'Financials'.