Select column from data.frame

Analogous function for select in dplyr.

select_dt(data, ...)

Arguments

data	data.frame
...	List of variables or name-value pairs of summary/modifications functions.

Value

data.table

See also

select,dt_mutate

Examples

  iris %>% select_dt(1,3,4)
#>      Sepal.Length Petal.Length Petal.Width
#>   1:          5.1          1.4         0.2
#>   2:          4.9          1.4         0.2
#>   3:          4.7          1.3         0.2
#>   4:          4.6          1.5         0.2
#>   5:          5.0          1.4         0.2
#>  ---                                      
#> 146:          6.7          5.2         2.3
#> 147:          6.3          5.0         1.9
#> 148:          6.5          5.2         2.0
#> 149:          6.2          5.4         2.3
#> 150:          5.9          5.1         1.8
  iris %>% select_dt(2:3)
#>      Sepal.Width Petal.Length
#>   1:         3.5          1.4
#>   2:         3.0          1.4
#>   3:         3.2          1.3
#>   4:         3.1          1.5
#>   5:         3.6          1.4
#>  ---                         
#> 146:         3.0          5.2
#> 147:         2.5          5.0
#> 148:         3.0          5.2
#> 149:         3.4          5.4
#> 150:         3.0          5.1
  iris %>% select_dt(Sepal.Length)
#>      Sepal.Length
#>   1:          5.1
#>   2:          4.9
#>   3:          4.7
#>   4:          4.6
#>   5:          5.0
#>  ---             
#> 146:          6.7
#> 147:          6.3
#> 148:          6.5
#> 149:          6.2
#> 150:          5.9
  iris %>% select_dt(Sepal.Length,Species)
#>      Sepal.Length   Species
#>   1:          5.1    setosa
#>   2:          4.9    setosa
#>   3:          4.7    setosa
#>   4:          4.6    setosa
#>   5:          5.0    setosa
#>  ---                       
#> 146:          6.7 virginica
#> 147:          6.3 virginica
#> 148:          6.5 virginica
#> 149:          6.2 virginica
#> 150:          5.9 virginica
  iris %>% select_dt(-Sepal.Length,-Species)
#>      Sepal.Width Petal.Length Petal.Width
#>   1:         3.5          1.4         0.2
#>   2:         3.0          1.4         0.2
#>   3:         3.2          1.3         0.2
#>   4:         3.1          1.5         0.2
#>   5:         3.6          1.4         0.2
#>  ---                                     
#> 146:         3.0          5.2         2.3
#> 147:         2.5          5.0         1.9
#> 148:         3.0          5.2         2.0
#> 149:         3.4          5.4         2.3
#> 150:         3.0          5.1         1.8
  iris %>% select_dt(startsWith(colnames(.),"Petal"))
#>      Petal.Length Petal.Width
#>   1:          1.4         0.2
#>   2:          1.4         0.2
#>   3:          1.3         0.2
#>   4:          1.5         0.2
#>   5:          1.4         0.2
#>  ---                         
#> 146:          5.2         2.3
#> 147:          5.0         1.9
#> 148:          5.2         2.0
#> 149:          5.4         2.3
#> 150:          5.1         1.8