dcast和聚合长度(R)

Question

我在R中有以下数据

   ID   credit_active    credit_currency      credit_type
   1    Active           Dollars              Home
   1    Closed           Dollars              Home
   1    Active           Euro                 Home
   2    Active           Dollars              Home
   2    Closed           Dollars              Home
   2    Active           Euro                 Home

我想要下列格式的数据

   ID     Active    Closed     Dollars     Euro     Home
   1      2         1          2           1        3
   2      2         1          2           1        3

我正在使用dcast函数来完成上面的工作。

  dcast_bureau <- dcast(setDT(bureau),ID~ credit_active + credit_currency + credit_type,
                  value.var = c("credit_active ","credit_currency ","credit_type")
                  ,fun.aggregate = length)       

但它并没有给我想要的格式。我怎么才能在r中做到呢？

Answer 1

我们需要melt和dcast。如果存在重复元素，默认情况下，fun.aggregate为length。

dcast(melt(setDT(bureau), id.var = 'ID'), ID ~ value)
#    ID Active Closed Dollars Euro Home
#1:  1      2      1       2    1    3
#2:  2      2      1       2    1    3

在reshape2中，有一个方便的包装器recast (melt + dcast)，它可以使它更加紧凑。

library(reshape2)
recast(bureau, id.var = 'ID', ID ~ value)