用重复行重新塑造数据帧

Question

我有一个数据框架，如下所示：

master_bill_no  category
SBA5100008  CONDOMS
SBA5100008  HAND CREAM
SBA5100009  PREGNANCY TESTS
SBA5100010  MULTI VITAMINS & MIN
SBA5100010  CALCIUM PREPARATIONS
SBA5100010  VITAMINS
SBA5100010  BETABLOCKERS

以下是一个可重复的例子：

structure(list(master_bill_no = c("SBA5100008", "SBA5100008", 
"SBA5100009", "SBA5100010", "SBA5100010", "SBA5100010", "SBA5100010"
), category = c("CONDOMS", "HAND CREAM", "PREGNANCY TESTS", "MULTI VITAMINS & MIN", 
"CALCIUM PREPARATIONS", "VITAMINS", "BETABLOCKERS")), .Names = c("master_bill_no", 
"category"), class = "data.frame", row.names = c(NA, -7L))

对于每一个独特的主账单不，我试图重塑专栏类别的宽。

例如，所需的输出是：

master_bill_no  category
SBA5100008  CONDOMS,HAND CREAM
SBA5100009  PREGNANCY TESTS
SBA5100010  MULTI VITAMINS & MIN,CALCIUM PREPARATIONS,CALCIUM PREPARATIONS,BETABLOCKERS

我使用了基本的重塑公式，它只是删除了类别列。

reshape(df, idvar = "master_bill_no", timevar = "category", direction = "wide")

我尝试了聚合函数：

aggregate(df, master_bill_no, FUN = paste(category, sep = ","))

这将返回一个错误消息“对象类别未找到”。

我相信这样做的原因是为了寻找价值填补，这是缺失的。有人能帮忙吗？

Answer 1

imho -最好使用基本函数，如聚合:正确的语法应该是：

aggregate(df$category, by=list(df$master_bill_no), FUN = paste)
         ( the field ,    list of 'group by'     , the fun to operate on field )

>df
  master_bill_no             category
1     SBA5100008              CONDOMS
2     SBA5100008           HAND CREAM
3     SBA5100009      PREGNANCY TESTS
4     SBA5100010 MULTI VITAMINS & MIN
5     SBA5100010 CALCIUM PREPARATIONS
6     SBA5100010             VITAMINS
7     SBA5100010         BETABLOCKERS


> aggregate(df$category, by=list(df$master_bill_no), FUN = paste)
     Group.1                                                                  x
1 SBA5100008                                                CONDOMS, HAND CREAM
2 SBA5100009                                                    PREGNANCY TESTS
3 SBA5100010 MULTI VITAMINS & MIN, CALCIUM PREPARATIONS, VITAMINS, BETABLOCKERS