我需要快速帮助。这很容易，但我被卡住了......
请使用示例：
mtcars
mpg cyl disp hp drat wt qsec vs am gear carb
Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4
Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4
Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1
Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1
Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2
Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1
Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4
Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2
Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2
Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4
Merc 280C 17.8 6 167.6 123 3.92 3.440 18.90 1 0 4 4
Merc 450SE 16.4 8 275.8 180 3.07 4.070 17.40 0 0 3 3
Merc 450SL 17.3 8 275.8 180 3.07 3.730 17.60 0 0 3 3
Merc 450SLC 15.2 8 275.8 180 3.07 3.780 18.00 0 0 3 3
Cadillac Fleetwood 10.4 8 472.0 205 2.93 5.250 17.98 0 0 3 4
Lincoln Continental 10.4 8 460.0 215 3.00 5.424 17.82 0 0 3 4
Chrysler Imperial 14.7 8 440.0 230 3.23 5.345 17.42 0 0 3 4
Fiat 128 32.4 4 78.7 66 4.08 2.200 19.47 1 1 4 1
Honda Civic 30.4 4 75.7 52 4.93 1.615 18.52 1 1 4 2
Toyota Corolla 33.9 4 71.1 65 4.22 1.835 19.90 1 1 4 1
Toyota Corona 21.5 4 120.1 97 3.70 2.465 20.01 1 0 3 1
Dodge Challenger 15.5 8 318.0 150 2.76 3.520 16.87 0 0 3 2
AMC Javelin 15.2 8 304.0 150 3.15 3.435 17.30 0 0 3 2
Camaro Z28 13.3 8 350.0 245 3.73 3.840 15.41 0 0 3 4
Pontiac Firebird 19.2 8 400.0 175 3.08 3.845 17.05 0 0 3 2
Fiat X1-9 27.3 4 79.0 66 4.08 1.935 18.90 1 1 4 1
Porsche 914-2 26.0 4 120.3 91 4.43 2.140 16.70 0 1 5 2
Lotus Europa 30.4 4 95.1 113 3.77 1.513 16.90 1 1 5 2
Ford Pantera L 15.8 8 351.0 264 4.22 3.170 14.50 0 1 5 4
Ferrari Dino 19.7 6 145.0 175 3.62 2.770 15.50 0 1 5 6
Maserati Bora 15.0 8 301.0 335 3.54 3.570 14.60 0 1 5 8
Volvo 142E 21.4 4 121.0 109 4.11 2.780 18.60 1 1 4 2
所以我想只保留哪些名称可以在另一个矩阵中找到：
> dput(list_names)
structure(c("Mazda RX4", "Mazda RX4 Wag", "Datsun 710", "Hornet 4 Drive",
"Hornet Sportabout", "Duster 360", "Merc 240D", "Merc 230",
"Merc 280", "Merc 280C", "Merc 450SE", "Merc 450SLC",
"Cadillac Fleetwood", "Chrysler Imperial",
"Fiat 128", "Honda Civic", "Toyota Corolla", "Toyota Corona",
"Dodge Challenger", "AMC Javelin", "Camaro Z28", "Pontiac Firebird",
"Fiat X1-9", "Lotus Europa", "Ford Pantera L",
"Ferrari Dino", "Maserati Bora", "Volvo 142E"), .Dim = c(32L,
1L))
如何有效地对其进行子集化？
答案 0 :(得分：4)
使用%in%功能：
subset <- mtcars[row.names(mtcars) %in% list_names[,1],]
答案 1 :(得分：0)
或者你可以试试：
mtcars[grep(paste(list_names, collapse="|"), row.names(mtcars)),]
假设数据集的row.names有额外的空格（前导/尾随空格）
mtcars1 <- mtcars
row.names(mtcars1)[9] <- "Merc 230 "
list_names <- c("Duster 360", "Merc 230", "Merc 280C", "Merc 280")
mtcars1[grep(paste(list_names, collapse="|"), row.names(mtcars1)),]
# mpg cyl disp hp drat wt qsec vs am gear carb
#Duster 360 14.3 8 360.0 245 3.21 3.57 15.84 0 0 3 4
#Merc 230 22.8 4 140.8 95 3.92 3.15 22.90 1 0 4 2
#Merc 280 19.2 6 167.6 123 3.92 3.44 18.30 1 0 4 4
#Merc 280C 17.8 6 167.6 123 3.92 3.44 18.90 1 0 4 4