[英]Create a new column in a dataframe and insert data in it based on row names in R
讓我們寫一個可重現的例子。 我將使用data(mtcars)
。
此數據集的每一行都有行名稱:
row.names(mtcars)
[1] "Mazda RX4" "Mazda RX4 Wag" "Datsun 710" "Hornet 4 Drive"
[5] "Hornet Sportabout" "Valiant" "Duster 360" "Merc 240D"
[9] "Merc 230" "Merc 280" "Merc 280C" "Merc 450SE"
[13] "Merc 450SL" "Merc 450SLC" "Cadillac Fleetwood" "Lincoln Continental"
[17] "Chrysler Imperial" "Fiat 128" "Honda Civic" "Toyota Corolla"
[21] "Toyota Corona" "Dodge Challenger" "AMC Javelin" "Camaro Z28"
[25] "Pontiac Firebird" "Fiat X1-9" "Porsche 914-2" "Lotus Europa"
[29] "Ford Pantera L" "Ferrari Dino" "Maserati Bora" "Volvo 142E"
現在我有另一個 dataframe:
df2 <- structure(list(Cluster = c("Group 1", "Group 1", "Group 1", "Group 1",
"Group 1", "Group 1", "Group 1", "Group 1", "Group 2", "Group 2",
"Group 2", "Group 2", "Group 2", "Group 2", "Group 2")), row.names = c("Mazda RX4",
"Mazda RX4 Wag", "Datsun 710", "Hornet 4 Drive", "Hornet Sportabout",
"Valiant", "Duster 360", "Merc 240D", "Merc 230", "Merc 280",
"Merc 280C", "Merc 450SE", "Merc 450SL", "Merc 450SLC", "Cadillac Fleetwood"
), class = "data.frame")
df2
Cluster
Mazda RX4 Group 1
Mazda RX4 Wag Group 1
Datsun 710 Group 1
Hornet 4 Drive Group 1
Hornet Sportabout Group 1
Valiant Group 1
Duster 360 Group 1
Merc 240D Group 1
Merc 230 Group 2
Merc 280 Group 2
Merc 280C Group 2
Merc 450SE Group 2
Merc 450SL Group 2
Merc 450SLC Group 2
Cadillac Fleetwood Group 2
我想做的是在原始mtcars
數據集 ( mtcars$Cluster
) 中創建一個新列,其中包含df2$Cluster
列的信息,遵循以下規則:
df2
中的行名也出現在mtcars
的行名中。mtcars$Cluster
中引入df2$Cluster
中存在的值。請注意,這是一個示例,但我的原始數據框:
df2
中的某些行名稱可能不在mtcars
中。mtcars
和df2
之間排序。任何想法?
你所描述的是一個join 。
例如在dplyr
中作為left_join
實現。 但是,要對行名稱執行此類連接,您首先要將它們移動到一列(此處使用 tibble 中的tibble
)。 如果你想 go 之后使用另一種方式使用column_to_rownames()
。
library(dplyr)
mtcars |>
rownames_to_column() |>
left_join(rownames_to_column(df2))
Output:
rowname mpg cyl disp hp drat wt qsec vs am gear carb Cluster
1 Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 Group 1
2 Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 Group 1
3 Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 Group 1
4 Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 Group 1
5 Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 Group 1
6 Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 Group 1
7 Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 Group 1
8 Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 Group 1
9 Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 Group 2
10 Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 Group 2
11 Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4 Group 2
12 Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3 Group 2
13 Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3 Group 2
14 Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3 Group 2
15 Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4 Group 2
16 Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4 <NA>
17 Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4 <NA>
18 Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 <NA>
19 Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 <NA>
20 Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 <NA>
21 Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 <NA>
22 Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2 <NA>
23 AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2 <NA>
24 Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4 <NA>
25 Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2 <NA>
26 Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 <NA>
27 Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 <NA>
28 Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 <NA>
29 Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4 <NA>
30 Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6 <NA>
31 Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8 <NA>
32 Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 <NA>
在基地 R 中:
df <- mtcars
df$Cluster <- df2[rownames(df), 'Cluster']
這也將保留行名稱:
df
# mpg cyl disp hp drat wt qsec vs am gear carb Cluster
# Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4 Group 1
# Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4 Group 1
# Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1 Group 1
# Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1 Group 1
# Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2 Group 1
# Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1 Group 1
# Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4 Group 1
# Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2 Group 1
# Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2 Group 2
# Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4 Group 2
# Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4 Group 2
# Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3 Group 2
# Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3 Group 2
# Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3 Group 2
# Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4 Group 2
# Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4 <NA>
# Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4 <NA>
# Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1 <NA>
# Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2 <NA>
# Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1 <NA>
# Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1 <NA>
# Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2 <NA>
# AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2 <NA>
# Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4 <NA>
# Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2 <NA>
# Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1 <NA>
# Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2 <NA>
# Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2 <NA>
# Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4 <NA>
# Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6 <NA>
# Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8 <NA>
# Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2 <NA>
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