cast in reshape and reshape2

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?

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.

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.

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.

?plyr::summarise seems pretty helpful to me.  If you can do better,
please submit a patch - they are very much appreciated.

?plyr::summarise seems pretty helpful to me. ?If you can do better,
please submit a patch - they are very much appreciated.

My failure to find it stemmed from it not being mentioned in any way in
package reshape2's help files, but maybe I was mistaken that it was meant to
be used in that context?