从数据框中删除重复的单词

Question

让我们用一个例子:

> dput(data)
structure(list(mpg = c(15.2, 10.4, 13.3, 14.7, 22.8, 15.5, 14.3, 
19.7, 32.4, 27.3, 15.8, 30.4, 21.4, 18.7, 10.4, 30.4, 15, 21, 
21, 22.8, 24.4, 19.2, 17.8, 16.4, 17.3, 15.2, 19.2, 26, 33.9, 
21.5, 18.1, 21.4), cyl = c(8, 8, 8, 8, 4, 8, 8, 6, 4, 4, 8, 4, 
6, 8, 8, 4, 8, 6, 6, 4, 4, 6, 6, 8, 8, 8, 8, 4, 4, 4, 6, 4), 
    disp = c(304, 472, 350, 440, 108, 318, 360, 145, 78.7, 79, 
    351, 75.7, 258, 360, 460, 95.1, 301, 160, 160, 140.8, 146.7, 
    167.6, 167.6, 275.8, 275.8, 275.8, 400, 120.3, 71.1, 120.1, 
    225, 121), hp = c(150, 205, 245, 230, 93, 150, 245, 175, 
    66, 66, 264, 52, 110, 175, 215, 113, 335, 110, 110, 95, 62, 
    123, 123, 180, 180, 180, 175, 91, 65, 97, 105, 109), drat = c(3.15, 
    2.93, 3.73, 3.23, 3.85, 2.76, 3.21, 3.62, 4.08, 4.08, 4.22, 
    4.93, 3.08, 3.15, 3, 3.77, 3.54, 3.9, 3.9, 3.92, 3.69, 3.92, 
    3.92, 3.07, 3.07, 3.07, 3.08, 4.43, 4.22, 3.7, 2.76, 4.11
    ), wt = c(3.435, 5.25, 3.84, 5.345, 2.32, 3.52, 3.57, 2.77, 
    2.2, 1.935, 3.17, 1.615, 3.215, 3.44, 5.424, 1.513, 3.57, 
    2.62, 2.875, 3.15, 3.19, 3.44, 3.44, 4.07, 3.73, 3.78, 3.845, 
    2.14, 1.835, 2.465, 3.46, 2.78), qsec = c(17.3, 17.98, 15.41, 
    17.42, 18.61, 16.87, 15.84, 15.5, 19.47, 18.9, 14.5, 18.52, 
    19.44, 17.02, 17.82, 16.9, 14.6, 16.46, 17.02, 22.9, 20, 
    18.3, 18.9, 17.4, 17.6, 18, 17.05, 16.7, 19.9, 20.01, 20.22, 
    18.6), vs = c(0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 
    1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1), am = c(0, 
    0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 
    0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1), gear = c(3, 3, 3, 3, 
    4, 3, 3, 5, 4, 4, 5, 4, 3, 3, 3, 5, 5, 4, 4, 4, 4, 4, 4, 
    3, 3, 3, 3, 5, 4, 3, 3, 4), carb = c(2, 4, 4, 4, 1, 2, 4, 
    6, 1, 1, 4, 2, 1, 2, 4, 2, 8, 4, 4, 2, 2, 4, 4, 3, 3, 3, 
    2, 2, 1, 1, 1, 2), car = structure(c(18L, 19L, 5L, 13L, 14L, 
    31L, 7L, 21L, 20L, 22L, 23L, 24L, 25L, 26L, 2L, 15L, 4L, 
    9L, 12L, 29L, 30L, 6L, 1L, 3L, 27L, 10L, 28L, 16L, 11L, 8L, 
    17L, 32L), .Label = c("AMC Javelin, AMC Javelin, AMC Javelin, AMC Javelin, AMC Javelin", 
    "Cadillac Fleetwood", "Camaro Z28", "Chrysler Imperial", 
    "Datsun 710, Datsun 710, Datsun 710, Datsun 710", "Dodge Challenger", 
    "Duster 360", "Ferrari Dino, Ferrari Dino, Ferrari Dino, Ferrari Dino, Ferrari Dino", 
    "Fiat 128, Fiat 128, Fiat 128, Fiat 128, Fiat 128", "Fiat X1-9", 
    "Ford Pantera L", "Honda Civic, Honda Civic, Honda Civic, Honda Civic, Honda Civic", 
    "Hornet 4 Drive, Hornet 4 Drive, Hornet 4 Drive, Hornet 4 Drive, Hornet 4 Drive", 
    "Hornet Sportabout", "Lincoln Continental", "Lotus Europa", 
    "Maserati Bora", "Mazda RX4", "Mazda RX4 Wag, Mazda RX4 Wag, Mazda RX4 Wag, Mazda RX4 Wag, Mazda RX4 Wag", 
    "Merc 230", "Merc 240D", "Merc 280", "Merc 280C", "Merc 450SE", 
    "Merc 450SL", "Merc 450SLC", "Pontiac Firebird", "Porsche 914-2", 
    "Toyota Corolla", "Toyota Corona", "Valiant", "Volvo 142E"
    ), class = "factor")), .Names = c("mpg", "cyl", "disp", "hp", 
"drat", "wt", "qsec", "vs", "am", "gear", "carb", "car"), 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", 
"Lincoln Continental", "Chrysler Imperial", "Fiat 128", "Honda Civic", 
"Toyota Corolla", "Toyota Corona", "Dodge Challenger", "AMC Javelin", 
"Camaro Z28", "Pontiac Firebird", "Fiat X1-9", "Porsche 914-2", 
"Lotus Europa", "Ford Pantera L", "Ferrari Dino", "Maserati Bora", 
"Volvo 142E"), class = "data.frame")

如您所见,我们在列中有一些重复的单词car.我想在每个单元格中只保留一个单词/短语.在我的原始数据中,单词也被昏迷分开.在我的原始数据中,我可能在不同的列中有相同的单词,我想保留原样.该函数应仅用于此特定列.

Answer 1

一种选择是使用正则表达式来检查每一行中是否有逗号,如果满足条件,则只保留前面的内容

sub(",.*", "", data$car)