Preserves the fred_tbl class and fred_query attribute when subsetting
rows or columns. Falls back to a plain vector when drop = TRUE reduces
the result to a single column (matching data.frame behaviour).
# S3 method for fred_tbl
[(x, i, j, ..., drop = TRUE)A fred_tbl (or a vector if drop collapses the result).
A fred_tbl.
Row selector.
Column selector.
Other arguments passed to [.data.frame.
Logical. As in [.data.frame.