Deleting specific obs for specific variables in R

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I'm working on a questionnaire and I need to turn some observations to NA when two arguments are true. In this case, I want my values to be NA when the variable name starts with "Q" and when the token is equals to the obs I no longer want.

So far I came up with this, which does not work.

Fusion_2_nom <- Fusion_2_nom %>%
  mutate_at(vars(starts_with("Q")),
            replace(token %in% c("3d4faa","214c61", "a786b6", "52a719", "1f9887", "9b6347"), NA))

How should I go about it?

Thanks!

3 Answers

You need to use a lambda function with replace, and the current column .xas imput. I suggest you use updated dplyr synthax( mutate(across(...)), instead of the deprecated mutate_at(vars(...))).

library(dplyr)

Fusion_2_nom <- Fusion_2_nom %>%
        mutate(across(starts_with("Q"),
                      ~replace(.x, token %in% c("3d4faa","214c61", "a786b6", "52a719", "1f9887", "9b6347"), NA))

A similar example with the mtcars dataset:

mtcars %>% mutate(across(vs:carb, ~replace(.x, mpg %in% c(21.0, 10.4, 15.0), NA)))

                     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 NA NA   NA   NA
Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02 NA NA   NA   NA
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 NA NA   NA   NA
Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82 NA NA   NA   NA
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 NA NA   NA   NA
Volvo 142E          21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

My approach would be similar, but I prefer to use across and if_else. Also for a better "readability" I created a separated vector for the tokens.

token_na <- c("3d4faa","214c61", "a786b6", "52a719", "1f9887", "9b6347")

df %>%
  mutate(
    across(
      .cols = starts_with("Q"),
      .fns = function(x)if_else(x %in% token_na,NA_character_,x))
  )

Using case_when

Fusion_2_nom %>%
  mutate(across(starts_with("Q")),
            case_when(!token %in% c("3d4faa","214c61", "a786b6", "52a719", "1f9887", "9b6347")~ .)))
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