This function makes it possible to control the ordering of window functions in R that don't have a specific ordering parameter. When translated to SQL it will modify the order clause of the OVER function.

order_by(order_by, call)

Arguments

order_by

a vector to order_by

call

a function call to a window function, where the first argument is the vector being operated on

Details

This function works by changing the call to instead call with_order() with the appropriate arguments.

Examples

order_by(10:1, cumsum(1:10))
#> [1] 55 54 52 49 45 40 34 27 19 10
x <- 10:1 y <- 1:10 order_by(x, cumsum(y))
#> [1] 55 54 52 49 45 40 34 27 19 10
df <- data.frame(year = 2000:2005, value = (0:5) ^ 2) scrambled <- df[sample(nrow(df)), ] wrong <- mutate(scrambled, running = cumsum(value)) arrange(wrong, year)
#> year value running #> 1 2000 0 38 #> 2 2001 1 55 #> 3 2002 4 29 #> 4 2003 9 38 #> 5 2004 16 54 #> 6 2005 25 25
right <- mutate(scrambled, running = order_by(year, cumsum(value))) arrange(right, year)
#> year value running #> 1 2000 0 0 #> 2 2001 1 1 #> 3 2002 4 5 #> 4 2003 9 14 #> 5 2004 16 30 #> 6 2005 25 55