Question

我在 R 中有 2 个不同的数据框

df1：

<头>

#	V1	V2
1	200	300
2	201	301
3	202	302

df2：

<头>

#	V1	V2	周
1	200	300	12-02-2018
2	301	201	25-05-2017
3	302	202	02-12-2016

我希望将它们与 VLOOKUP 等效项合并在一起。

想法是将周从 df2 添加到 df1 IF：

(df1$V1 == df2$V1 & df1$V2 == df2$V2) 或 (df1$V1 == df2$V2 & df1$V2 == df2$V1).

由于 V1 和 V2 是随机分配的，所以我需要条件双向进行。

有什么帮助吗？

非常感谢！

Answer 1

对两个数据框中的列 V1 和 V2 进行排序，然后执行 merge。

df1 <- transform(df1, V1 = pmin(V1, V2), V2 = pmax(V1, V2))
df2 <- transform(df2, V1 = pmin(V1, V2), V2 = pmax(V1, V2))
merge(df1, df2, by = c('id', 'V1', 'V2'))

#  id  V1  V2       week
#1  1 200 300 12-02-2018
#2  2 201 301 25-05-2017
#3  3 202 302 02-12-2016

数据

df1 <- structure(list(id = 1:3, V1 = 200:202, V2 = 300:302), 
       row.names = c(NA, -3L), class = "data.frame")

df2 <- structure(list(id = 1:3, V1 = c(200L, 301L, 302L), V2 = c(300L, 
201L, 202L), week = c("12-02-2018", "25-05-2017", "02-12-2016"
)), row.names = c(NA, -3L), class = "data.frame")

Answer 2

您可以先在 V1 (df1) = V1 (df2) 和 V2 (df1) = V2 (df2) 上合并，然后从 df1 中获取不满足这些条件的行。有了这些行，您现在可以使用 V1 (df1) = V2 (df2) 和 V2 (df1) = V1 (df2) 进行第二次合并，从而按照您所述的顺序模仿“OR”条件。

#Replicates of your dataframes
df1 <- data.frame(matrix(c(1, 200, 300, 
                           2, 201, 301, 
                           3, 202, 302), ncol=3, byrow = TRUE))
colnames(df1) <- c("iddf1", "V1", "V2")

df2 <- data.frame(matrix(c(1, 200, 300, "12-02-2018",
                           2, 301, 201, "25-05-2017",
                           3, 302, 202, "02-12-2016"), ncol=4, byrow = TRUE))
colnames(df2) <- c("iddf2", "V1", "V2", "week")

#Merge first on V1 (df1) = V2 (df2) and V2 (df1) = V2 (df2)
df.merged.1 <- merge(df1, df2, by = c("V1", "V2"), all.x = T)

#Extract the rows that did dot match
df1.unmet <- df.merged.1[is.na(df.merged.1$iddf2),c("iddf1", "V1", "V2")]
df.merged.1 <- df.merged.1[!is.na(df.merged.1$iddf2),]

#Merge then on V2 (df1) = V1 (df2) and V2 (df1) = V1 (df2)
df.merged.2 <- merge(df1.unmet, df2, by.x=c("V1", "V2"), by.y = c("V2", "V1"))

#rbind the two dataframes to get the final result
df.merged <- rbind(df.merged.1, df.merged.2)
df.merged
#   V1  V2 iddf1 iddf2       week
#1 200 300     1     1 12-02-2018
#2 201 301     2     2 25-05-2017
#3 202 302     3     3 02-12-2016

R中的条件VLOOKUP等价物（数据帧）

2 个答案: