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d <- data.frame(
id = 1:6,
mpg = c(21, 21, 22.8, 21.4, 18.7, 18.1), cyl = c(6, 6, 4, 6, 8, 6),
disp = c(160, 160, 108, 258, 360, 225),
hp = c(110, 110, 93, 110, 175, 105),
drat = c(3.9, 3.9,3.85, 3.08, 3.15, 2.76),
wt = c(2.62, 2.875, 2.32, 3.215, 3.44,3.46),
qsec = c(16.46, 17.02, 18.61, 19.44, 17.02, 20.22),
vs = c( 0,0, 1, 1, 0, 1),
am = c(1, 1, 1, 0, 0, 0),
gear = c(4, 4, 4, 3,3, 3),
carb = c(4, 4, 1, 1, 2, 1))
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 1 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
#> 2 2 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
#> 3 3 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
# change mpg for id 1 to 22.0 (row1,col1)
d[1,1] <- 22
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4
#> 2 2 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4
#> 3 3 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
# change disp for id1 and id2 to 180
d[1:2,4] <- 180
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 180 110 3.90 2.620 16.46 0 1 4 4
#> 2 2 21.0 6 180 110 3.90 2.875 17.02 0 1 4 4
#> 3 3 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1
# change all carb to 4
d[12] <- 4
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 180 110 3.90 2.620 16.46 0 1 4 4
#> 2 2 21.0 6 180 110 3.90 2.875 17.02 0 1 4 4
#> 3 3 22.8 4 108 93 3.85 2.320 18.61 1 1 4 4
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 3 4
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 3 4
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 3 4
# change all gear to 4
d$gear <- 4
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 180 110 3.90 2.620 16.46 0 1 4 4
#> 2 2 21.0 6 180 110 3.90 2.875 17.02 0 1 4 4
#> 3 3 22.8 4 108 93 3.85 2.320 18.61 1 1 4 4
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 4 4
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 4 4
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 4 4
# change id4 hp and drat
d[3,5:6] <- c(100,3.9)
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 180 110 3.90 2.620 16.46 0 1 4 4
#> 2 2 21.0 6 180 110 3.90 2.875 17.02 0 1 4 4
#> 3 3 22.8 4 108 100 3.90 2.320 18.61 1 1 4 4
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 4 4
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 4 4
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 4 4
# change any am 1 to am 0
d[which(d$am == 1),"am"] <- 0
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 180 110 3.90 2.620 16.46 0 0 4 4
#> 2 2 21.0 6 180 110 3.90 2.875 17.02 0 0 4 4
#> 3 3 22.8 4 108 100 3.90 2.320 18.61 1 0 4 4
#> 4 4 21.4 6 258 110 3.08 3.215 19.44 1 0 4 4
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 4 4
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 4 4
# change qsec to 20 if vs == 1 and hp > 105
d[which(d$vs == 1 & d$hp > 105),8] <- 20
d
#> id mpg cyl disp hp drat wt qsec vs am gear carb
#> 1 22 21.0 6 180 110 3.90 2.620 16.46 0 0 4 4
#> 2 2 21.0 6 180 110 3.90 2.875 17.02 0 0 4 4
#> 3 3 22.8 4 108 100 3.90 2.320 18.61 1 0 4 4
#> 4 4 21.4 6 258 110 3.08 3.215 20.00 1 0 4 4
#> 5 5 18.7 8 360 175 3.15 3.440 17.02 0 0 4 4
#> 6 6 18.1 6 225 105 2.76 3.460 20.22 1 0 4 4
Created on 2023-06-12 with reprex v2.0.2