相关疑难解决方法(0)

我想重塑我的数据帧从长格式到宽格式,我放弃了一些我想保留的数据.对于以下示例:

df <- data.frame(Par1 = unlist(strsplit("AABBCCC","")),
                 Par2 = unlist(strsplit("DDEEFFF","")),
                 ParD = unlist(strsplit("foo,bar,baz,qux,bla,xyz,meh",",")),
                 Type = unlist(strsplit("pre,post,pre,post,pre,post,post",",")),
                 Val = c(10,20,30,40,50,60,70))

   #     Par1 Par2 ParD Type Val
   #   1    A    D  foo  pre  10
   #   2    A    D  bar post  20
   #   3    B    E  baz  pre  30
   #   4    B    E  qux post  40
   #   5    C    F  bla  pre  50
   #   6    C    F  xyz post  60
   #   7    C    F  meh post  70

dfw <- dcast(df,
             formula = Par1 + …

根据我的阅读,*reshape2中的演员操作失去了他们的result_variable功能.Hadley暗示为此目的使用plyr(将多个结果列附加到输入数据框).我怎么才能实现文档示例......

aqm <- melt(airquality, id=c("month", "day"), na.rm=TRUE)
cast(aqm, month ~ variable + result_variable, range)

使用reshape2(dcast)和plyr(ddply)？