cast in reshape and reshape2
On Dec 23, 2011, at 5:58 PM, David Winsemius wrote:
On Dec 23, 2011, at 2:58 PM, Kaiyin Zhong wrote:
library(reshape2)
x = melt(airquality, id=c('month', 'day'))
With reshape I can cast with multiple functions:
library(reshape) cast(x, month+variable~., c(mean,sd))
month variable mean sd 1 5 ozone 23.615385 22.224449 2 5 solar.r 181.296296 115.075499 3 5 wind 11.622581 3.531450 4 5 temp 65.548387 6.854870 5 6 ozone 29.444444 18.207904 6 6 solar.r 190.166667 92.882975 7 6 wind 10.266667 3.769234 8 6 temp 79.100000 6.598589 9 7 ozone 59.115385 31.635837 10 7 solar.r 216.483871 80.568344 11 7 wind 8.941935 3.035981 12 7 temp 83.903226 4.315513 13 8 ozone 59.961538 39.681210 14 8 solar.r 171.857143 76.834943 15 8 wind 8.793548 3.225930 16 8 temp 83.967742 6.585256 17 9 ozone 31.448276 24.141822 18 9 solar.r 167.433333 79.118280 19 9 wind 10.180000 3.461254 20 9 temp 76.900000 8.355671 Is there a way to do the same job with reshape2?
Have you looked at the .summarise argument to dcast? That seems to deliver the same sort of results one gets with base::aggregate.
Actually I see after looking at examples on the plyr-reshape- googlegroups group that it is not '.summarise' but rather 'summarise'. Unfortunately there are no links in the help pages that seem to describe its proper use ... a not uncommon failing for that package in my experience.
David Winsemius, MD West Hartford, CT