dt_count calculate number of cases by groups, possibly
weighted. dt_add_count adds number of cases to existing dataset
dt_top_n returns top n rows from each group.
dt_count(data, ..., weight = NULL, sort = FALSE, name = "n") dt_add_count(data, ..., weight = NULL, sort = FALSE, name = "n") dt_top_n(data, n, by, order_by = NULL)
| data | data.table/data.frame data.frame will be automatically converted to data.table. |
|---|---|
| ... | variables to group by. |
| weight | optional. Unquoted variable name. If provided result will be the sum of this variable by groups. |
| sort | logical. If TRUE result will be sorted in desending order by resulting variable. |
| name | character. Name of resulting variable. |
| n | numeric. number of top cases. If n is negative then bottom values will be returned. |
| by | list or vector of grouping variables |
| order_by | unquoted variable name by which result will be sorted. If not specified, defaults to the last variable in the dataset. |
data.table
#> am vs n #> 1: 1 0 6 #> 2: 1 1 7 #> 3: 0 1 7 #> 4: 0 0 12dt_add_count(mtcars, am, vs, name = "am_vs")[] # [] for autoprinting#> mpg cyl disp hp drat wt qsec vs am gear carb am_vs #> 1: 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 6 #> 2: 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 6 #> 3: 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 7 #> 4: 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 7 #> 5: 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 12 #> 6: 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 7 #> 7: 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 12 #> 8: 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 7 #> 9: 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 7 #> 10: 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 7 #> 11: 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4 7 #> 12: 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3 12 #> 13: 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3 12 #> 14: 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3 12 #> 15: 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4 12 #> 16: 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4 12 #> 17: 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4 12 #> 18: 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 7 #> 19: 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 7 #> 20: 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 7 #> 21: 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 7 #> 22: 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2 12 #> 23: 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2 12 #> 24: 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4 12 #> 25: 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2 12 #> 26: 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 7 #> 27: 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 6 #> 28: 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 7 #> 29: 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4 6 #> 30: 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6 6 #> 31: 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8 6 #> 32: 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 7 #> mpg cyl disp hp drat wt qsec vs am gear carb am_vs#> am vs mpg cyl disp hp drat wt qsec gear carb #> 1: 1 0 15.0 8 301.0 335 3.54 3.570 14.60 5 8 #> 2: 1 0 19.7 6 145.0 175 3.62 2.770 15.50 5 6 #> 3: 0 0 14.3 8 360.0 245 3.21 3.570 15.84 3 4 #> 4: 0 0 10.4 8 472.0 205 2.93 5.250 17.98 3 4 #> 5: 0 1 19.2 6 167.6 123 3.92 3.440 18.30 4 4 #> 6: 0 1 17.8 6 167.6 123 3.92 3.440 18.90 4 4 #> 7: 1 1 30.4 4 75.7 52 4.93 1.615 18.52 4 2 #> 8: 1 1 30.4 4 95.1 113 3.77 1.513 16.90 5 2#> am vs mpg cyl disp hp drat wt qsec gear carb #> 1: 1 1 33.9 4 71.1 65 4.22 1.835 19.90 4 1 #> 2: 1 1 32.4 4 78.7 66 4.08 2.200 19.47 4 1 #> 3: 1 0 26.0 4 120.3 91 4.43 2.140 16.70 5 2 #> 4: 1 0 21.0 6 160.0 110 3.90 2.620 16.46 4 4 #> 5: 0 1 24.4 4 146.7 62 3.69 3.190 20.00 4 2 #> 6: 0 1 22.8 4 140.8 95 3.92 3.150 22.90 4 2 #> 7: 0 0 19.2 8 400.0 175 3.08 3.845 17.05 3 2 #> 8: 0 0 18.7 8 360.0 175 3.15 3.440 17.02 3 2