using the same variable in aggregation and sorting in data table

[Just1234]

Hi, I have a code

proxy <-"Var1"
data[,.
     ( 
       count   = .N
       ,summm  = sum(PREMIUM)      
     ),
     
     by = c(proxy,'var2')][order(Var2, proxy)]

How do I use the same proxy in "by" and "order"?

the "by" requires variable to come with quotation marks, and "order" requires a variable without quotation marks.

Treid the proxy <-noquote("Var1"), but data.table also complains, which is hard to understand why.

Thanks

[martin.R]

You've muddles a few things.

R is case-sensitive, so var2 and Var2 are different objects.

You can mix quoted and unquoted variables, but you need to be aware how they are used:

library(data.table)

mt <- data.table(mtcars)

mt[, .N, by = c("cyl", "gear")] # use quotes when using a vector

mt[, .N, by = list(cyl, gear)] # don't use quotes when using a list

mt[, .N, .(cyl, gear)] # same but less typing

mt[, .N, keyby = .(cyl, gear)] # keyby keys (orders) the output