R dtplyr relocate.dtplyr_step 使用变量名称重新定位变量

# S3 method for dtplyr_step
relocate(.data, ..., .before = NULL, .after = NULL)

library(dplyr, warn.conflicts = FALSE)

dt <- lazy_dt(data.frame(x = 1, y = 2, z = 3))

dt %>% relocate(z)
#> Source: local data table [1 x 3]
#> Call:   setcolorder(copy(`_DT33`), c("z", "x", "y"))
#> 
#>       z     x     y
#>   <dbl> <dbl> <dbl>
#> 1     3     1     2
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results
dt %>% relocate(y, .before = x)
#> Source: local data table [1 x 3]
#> Call:   setcolorder(copy(`_DT33`), c("y", "x", "z"))
#> 
#>       y     x     z
#>   <dbl> <dbl> <dbl>
#> 1     2     1     3
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results
dt %>% relocate(y, .after = y)
#> Source: local data table [1 x 3]
#> Call:   `_DT33`
#> 
#>       x     y     z
#>   <dbl> <dbl> <dbl>
#> 1     1     2     3
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results