How to delete a particular value from the whole dataframe in R?-CodePudding

I have a data frame that is not z-score converted. I want to delete from the data frame (and convert to NA) only those values that are higher or equal to 4, without dropping any row or column. I would appreciate an answer.

Best

CodePudding user response：

You can use the following code:

df <- data.frame(v1 = c(1,3,6,7,3),
                 v2 = c(2,1,4,6,7),
                 v3 = c(1,2,3,4,5))
df
#>   v1 v2 v3
#> 1  1  2  1
#> 2  3  1  2
#> 3  6  4  3
#> 4  7  6  4
#> 5  3  7  5
is.na(df) <- df >= 4
df
#>   v1 v2 v3
#> 1  1  2  1
#> 2  3  1  2
#> 3 NA NA  3
#> 4 NA NA NA
#> 5  3 NA NA

^{Created on 2022-07-10 by the reprex package (v2.0.1)}

CodePudding user response：

you can simply use df[df>=4] <- NA to achieve what you want.

df <- data.frame(replicate(10,sample(0:10,10,rep=TRUE)))

> df
   X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1   2  3  4  5  6  4  3  1 10   6
2   5  7  0  4  3 10 10  3  6  10
3   5  5  0  3  1  3  5  7  2   7
4   7  0  4  1 10  0  5  2  5   0
5   8  8  7  8  4  6  6 10 10   0
6   1  4  1  3  3  8  8  0  4   8
7   6  3  3  6  7  4 10  9  7   2
8   2  1  4  0  7  8 10  1  6   3
9   0  9  6  2  9  6  2  9  0   3
10  8  2  1  0  1  4  0  6  2   8



df[df>=4] <- NA

> df
   X1 X2 X3 X4 X5 X6 X7 X8 X9 X10
1   2  3 NA NA NA NA  3  1 NA  NA
2  NA NA  0 NA  3 NA NA  3 NA  NA
3  NA NA  0  3  1  3 NA NA  2  NA
4  NA  0 NA  1 NA  0 NA  2 NA   0
5  NA NA NA NA NA NA NA NA NA   0
6   1 NA  1  3  3 NA NA  0 NA  NA
7  NA  3  3 NA NA NA NA NA NA   2
8   2  1 NA  0 NA NA NA  1 NA   3
9   0 NA NA  2 NA NA  2 NA  0   3
10 NA  2  1  0  1 NA  0 NA  2  NA

CodePudding user response：

Though the solution by @Quinten is very concise, just add an approach in tidyverse

library(dplyr)

set.seed(123)

df <- data.frame(
  x = sample(1:10, 7),
  y = sample(1:10, 7)
)

df %>% 
  mutate(
    across(.fns = ~ if_else(.x >= 4, NA_integer_, .x))
  )

#>    x  y
#> 1  3 NA
#> 2 NA NA
#> 3  2  1
#> 4 NA  2
#> 5 NA  3
#> 6 NA NA
#> 7  1 NA

^{Created on 2022-07-10 by the reprex package (v2.0.1)}