"Uncount" a database table

This is a method for the tidyr uncount() generic. It uses a temporary table, so your database user needs permissions to create one.

Usage

dbplyr_uncount(data, weights, .remove = TRUE, .id = NULL)

Arguments

data

A lazy data frame backed by a database query.

weights

A vector of weights. Evaluated in the context of data; supports quasiquotation.

.remove

If TRUE, and weights is the name of a column in data, then this column is removed.

.id

Supply a string to create a new variable which gives a unique identifier for each created row.

Examples

df <- memdb_frame(x = c("a", "b"), n = c(1, 2))
dbplyr_uncount(df, n)
#> # Source:   SQL [3 x 1]
#> # Database: sqlite 3.45.2 [:memory:]
#>   x    
#>   <chr>
#> 1 a    
#> 2 b    
#> 3 b    
dbplyr_uncount(df, n, .id = "id")
#> # Source:   SQL [3 x 2]
#> # Database: sqlite 3.45.2 [:memory:]
#>   x        id
#>   <chr> <int>
#> 1 a         1
#> 2 b         1
#> 3 b         2

# You can also use constants
dbplyr_uncount(df, 2)
#> # Source:   SQL [4 x 2]
#> # Database: sqlite 3.45.2 [:memory:]
#>   x         n
#>   <chr> <dbl>
#> 1 a         1
#> 2 a         1
#> 3 b         2
#> 4 b         2

# Or expressions
dbplyr_uncount(df, 2 / n)
#> # Source:   SQL [3 x 2]
#> # Database: sqlite 3.45.2 [:memory:]
#>   x         n
#>   <chr> <dbl>
#> 1 a         1
#> 2 a         1
#> 3 b         2