根據索引號在另一個資料框中添加一列

我有兩個非常大的資料框。第一個資料框有一個縣名串列及其相關的 fip 代碼。第二個資料集只有它們的 fip 代碼。

我想在第二個資料框中添加兩列及其關聯的縣名。

假設這是 df1

df1 = data.frame(countyname = c("Archuleta County, CO","Baca County, CO","Cheyenne County, CO","Kiowa County, CO","Cimarron County, OK","Rio Arriba County, NM","Conejos County, CO"),
                 fipscounty = c(8007,8009,8017,8061,35039,40025,8021))

countyname fipscounty
1  Archuleta County, CO       8007
2       Baca County, CO       8009
3   Cheyenne County, CO       8017
4      Kiowa County, CO       8061
5   Cimarron County, OK      35039
6 Rio Arriba County, NM      40025
7    Conejos County, CO       8021

編輯：這是 df2

df2 = data.frame(county1=c(8007,8007,8009,8017),
                 distance=c(4,3,2,1),
                 county2=c(35039,8021,40025,8061))
  county1 distance county2
1    8007        4   35039
2    8007        3    8021
3    8009        2   40025
4    8017        1    8061

編輯：我希望最終結果如下所示：

            countyname fipscounty distance        countyneighbor fipscounty2
1 Archuleta County, CO       8007        4   Cimarron County, OK       35039
2 Archuleta County, CO       8007        3    Conejos County, CO        8021
3      Baca County, CO       8009        2 Rio Arriba County, NM       40025
4  Cheyenne County, CO       8017        1      Kiowa County, CO        8061

我想使用 df1 和 df2 的 fips 代碼將縣名從 df1 轉移到 df2。由于它們沒有相同的列名，我可能不得不使用索引號來執行此操作。但是，我不想轉移整行，否則我會有重復的 fips 列。

我試過這個，但它當然出錯了

df2 <- left_join(df1,df2, by= df1[2])

我該怎么做？

uj5u.com熱心網友回復：

使用match.

m <- match(df2$county1, df1$fipscounty)
res <- cbind(df1[m, ], df1[match(df2$county2, df1$fipscounty), ])
names(res)[c(2, 4)] <- names(df2)[c(1, 3)]
res
#               countyname county1            countyname county2
# 1   Archuleta County, CO    8007   Cimarron County, OK   35039
# 1.1 Archuleta County, CO    8007    Conejos County, CO    8021
# 2        Baca County, CO    8009 Rio Arriba County, NM   40025
# 3    Cheyenne County, CO    8017      Kiowa County, CO    8061

編輯

根據您的編輯，您可以包含merge和append作為工具。

m1 <- merge(df1a, df2a, by.x='fipscounty', by.y='county1')[c(2, 1, 3:4)]
append(m1, 
       list(countyneighbor=df1a[match(m1$county2, df1a$fipscounty), 
                                'countyname']), 3) |>
  as.data.frame()

#             countyname fipscounty distance        countyneighbor county2
# 1 Archuleta County, CO       8007        4   Cimarron County, OK   35039
# 2 Archuleta County, CO       8007        3    Conejos County, CO    8021
# 3      Baca County, CO       8009        2 Rio Arriba County, NM   40025
# 4  Cheyenne County, CO       8017        1      Kiowa County, CO    8061

注意： 使用 R >= 4.1。

資料：

df1 <- structure(list(countyname = c("Archuleta County, CO", "Baca County, CO", 
"Cheyenne County, CO", "Kiowa County, CO", "Cimarron County, OK", 
"Rio Arriba County, NM", "Conejos County, CO"), fipscounty = c(8007, 
8009, 8017, 8061, 35039, 40025, 8021)), class = "data.frame", row.names = c(NA, 
-7L))

df2 <- structure(list(county1 = c(8007, 8007, 8009, 8017), county2 = c(35039, 
8021, 40025, 8061)), class = "data.frame", row.names = c(NA, 
-4L))

df1a <- structure(list(countyname = c("Archuleta County, CO", "Baca County, CO", 
"Cheyenne County, CO", "Kiowa County, CO", "Cimarron County, OK", 
"Rio Arriba County, NM", "Conejos County, CO"), fipscounty = c(8007, 
8009, 8017, 8061, 35039, 40025, 8021)), class = "data.frame", row.names = c(NA, 
-7L))

df2a <- structure(list(county1 = c(8007, 8007, 8009, 8017), distance = c(4, 
3, 2, 1), county2 = c(35039, 8021, 40025, 8061)), class = "data.frame", row.names = c(NA, 
-4L))

標籤：r 数据框 合并 数据操作

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