[R] data frame move columns

[Erik Iverson]

> avprix <-
> structure(list(DESCRIPTION = c("CORN Jul/10", "CORN May/10", 
> "ROBUSTA COFFEE (10) Jul/10", "SOYBEANS Jul/10", "SPCL HIGH GRADE ZINC USD",
> 
> "STANDARD LEAD USD"), prix = c(-1.5, -1082, 11084, 1983.5, -2464, 
> -118), quantity = c(0, -3, 8, 2, -1, 0), fees = c(-8.64, -30.24, 
> -26.4, -25.92, -37.5, -25)), .Names = c("DESCRIPTION", "prix", 
> "quantity", "fees"), row.names = c(NA, -6L), class = "data.frame")
> 
> I want to group together all the rows with quantity=0.
> 
> This following line does the job :
> 
>> avprix<-rbind(avprix[!avprix$quantity==0,],avprix[avprix$quantity==0,]).
> 
>

If you don't care that the 0s are at the end, but rather just grouped, 
just use 'order'.

avprix[order(avprix$quantity),]