Using Ifelse in R

Using ifelse() statements to get objects of different classes in R

ifelse requires all the arguments to be same length. Here, it is not the case. Therefore, we need if/else

if(is.data.frame(mtcars) ) get(mtcars__string_object) else NA

-ouptut

                  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

Recode age variable in my dataset using ifelse() function

Seems like case_when() is better here. You'll have to decide where the = operator goes i.e. are 28 year olds 'young' or 'middle'?

age <-  data.frame(age = c(15, 29, 54, 53, 28))
age %>%
  mutate(age_bracket = case_when(age >= 28 & age < 53 ~ "middle",
                                 age < 28 ~ "young",
                                 age >= 53 ~ "old"))
    

How to use R ifelse function with && function?

Potential duplicate: Boolean operators && and ||

If you use "&" instead of "&&" your command works as expected, e.g.

set.seed(111)
A <- rnorm(10,10,2)
B <- c(23,0,0,0,1,2,0,1,2,0)
C <- c(1,1,23,0,0,0,1,2,0,0)
D <- c(0,1,1,23,0,0,0,1,2,0)


df <- data.frame(A,B,C,D)
df$A.only <- ifelse(df$A > 0 & df$B == 0 & df$C == 0 & df$D == 0, 1, 0)

df
#>            A  B  C  D A.only
#> 1  10.470441 23  1  0      0
#> 2   9.338528  0  1  1      0
#> 3   9.376752  0 23  1      0
#> 4   5.395309  0  0 23      0
#> 5   9.658248  1  0  0      0
#> 6  10.280556  2  0  0      0
#> 7   7.005147  0  1  0      0
#> 8   7.979623  1  2  1      0
#> 9   8.103049  2  0  2      0
#> 10  9.012076  0  0  0      1

^{Created on 2022-04-04 by the reprex package (v2.0.1)}

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