
utils table manipulation methods for dm_zoomed
objects
Source: R/utils.R
utils_table_manipulation.Rd
Extract the first or last rows from a table.
Use these methods without the '.dm_zoomed' suffix (see examples).
The methods for regular dm
objects extract the first or last tables.
Arguments
- x
object of class
dm_zoomed
- n
an integer vector of length up to
dim(x)
(or 1, for non-dimensioned objects). Values specify the indices to be selected in the corresponding dimension (or along the length) of the object. A positive value ofn[i]
includes the first/lastn[i]
indices in that dimension, while a negative value excludes the last/firstabs(n[i])
, including all remaining indices.NA
or non-specified values (whenlength(n) < length(dim(x))
) select all indices in that dimension. Must contain at least one non-missing value.- ...
arguments to be passed to or from other methods.
Examples
zoomed <- dm_nycflights13() %>%
dm_zoom_to(flights) %>%
head(4)
zoomed
#> # Zoomed table: flights
#> # A tibble: 4 × 19
#> year month day dep_time sched_dep…¹ dep_d…² arr_t…³ sched…⁴ arr_d…⁵ carrier
#> <int> <int> <int> <int> <int> <dbl> <int> <int> <dbl> <chr>
#> 1 2013 1 10 3 2359 4 426 437 -11 B6
#> 2 2013 1 10 16 2359 17 447 444 3 B6
#> 3 2013 1 10 450 500 -10 634 648 -14 US
#> 4 2013 1 10 520 525 -5 813 820 -7 UA
#> # … with 9 more variables: flight <int>, tailnum <chr>, origin <chr>,
#> # dest <chr>, air_time <dbl>, distance <dbl>, hour <dbl>, minute <dbl>,
#> # time_hour <dttm>, and abbreviated variable names ¹sched_dep_time,
#> # ²dep_delay, ³arr_time, ⁴sched_arr_time, ⁵arr_delay
dm_insert_zoomed(zoomed, new_tbl_name = "head_flights")
#> ── Metadata ────────────────────────────────────────────────────────────────────
#> Tables: `airlines`, `airports`, `flights`, `planes`, `weather`, `head_flights`
#> Columns: 72
#> Primary keys: 4
#> Foreign keys: 8