Question

说我有此数据表：

Name  |  Pet  | Hobby    | Sibling
------------------------------------------
Bob   | Dog   | Running  | Linda
Ross  | Cat   | Hiking   | Howie
Linda | Mouse | Beaches  | Bob
Howie | Plant | Gaming   | Ross

因此，接下来，我想将同级的信息添加到同一行。兄弟姐妹的信息在表中。因此，基本上，您会找到同级的行，并将同级的“ Pet”和“ Hobby”行附加到该行中

Name  |  Pet  | Hobby    | Sibling | Sibling's Pet | Sibling Hobby's
-----------------------------------------------------------------
Bob   | Dog   | Running  | Linda   | Mouse         | Beaches     #Cols appended from Row 3 above
Ross  | Cat   | Hiking   | Howie   | Plant         | Gaming      #Cols appended from Row 4 above
Linda | Mouse | Beaches  | Bob     | Dog           | Running     #Cols appended from Row 1 above
Howie | Plant | Gaming   | Ross    | Cat           | Hiking      #Cols appended from Row 2 above

Answer 1

我们使用match创建一个索引，然后使用该索引来创建列

i1 <- with(df1, match(Name, Sibling))
df1[paste0("Siblings_", c("Pet", "Hobby"))] <- lapply(df1[2:3], function(x) x[i1])
df1
#   Name   Pet   Hobby Sibling Siblings_Pet Siblings_Hobby
#1   Bob   Dog Running   Linda        Mouse        Beaches
#2  Ross   Cat  Hiking   Howie        Plant         Gaming
#3 Linda Mouse Beaches     Bob          Dog        Running
#4 Howie Plant  Gaming    Ross          Cat         Hiking

Answer 2

这是使用自联接和按引用更新的data.table方法：

dt[dt, on = c("Sibling" = "Name"), `:=`(sib_pet = i.Pet, sib_hob = i.Hobby)]

#    Name   Pet   Hobby Sibling sib_pet sib_hob
#1:   Bob   Dog Running   Linda   Mouse Beaches
#2:  Ross   Cat  Hiking   Howie   Plant  Gaming
#3: Linda Mouse Beaches     Bob     Dog Running
#4: Howie Plant  Gaming    Ross     Cat  Hiking

R数据表添加不同行中的列

2 个答案: