相关疑难解决方法(0)

我试图理解为什么开发已经转变reshape为reshape2包装.它们似乎在功能上是相同的,但是,reshape2由于服务器上运行的旧版本的R ,我无法升级到当前.我担心一个主要错误的可能性会将开发转移到一个全新的包而不是简单地继续开发reshape.有谁知道reshape包装中是否存在重大缺陷？

是否可以在单个tapply或aggregate语句中包含两个函数？

下面我使用两个tapply语句和两个聚合语句:一个用于均值,一个用于SD.
我更愿意结合这些陈述.

my.Data = read.table(text = "
  animal    age     sex  weight
       1  adult  female     100
       2  young    male      75
       3  adult    male      90
       4  adult  female      95
       5  young  female      80
", sep = "", header = TRUE)

with(my.Data, tapply(weight, list(age, sex), function(x) {mean(x)}))
with(my.Data, tapply(weight, list(age, sex), function(x) {sd(x)  }))

with(my.Data, aggregate(weight ~ age + sex, FUN = mean)
with(my.Data, aggregate(weight ~ age + sex, FUN =   sd)

# this does not work:

with(my.Data, tapply(weight, list(age, sex), function(x) …