For loop to replace values with NA based on a condition in R

Question

I am trying to replace values with NA based on a condition. I have written the following code which works fine:

df <- df %>% 
mutate(var1 = ifelse(years > 0, NA, var1)

I need run this code for 80+ different variables, so I am trying to use a for loop (instead of copy-pasting). I have tried the following code, but it doesn't work

for(i in c(13:100))
   {df <- df %>% 
         mutate(i = ifelse(df$years > 0, NA, i))}

Ideally, the output of the loop will be stored back in the original dataframe. Thank you so much, any help is greatly appreciated!

The reason why we have mutate is to avoid the for loops, you should consider `mutate(across(your_variables, ~\`is.na<-\`(.x, .x>0)))` — Onyambu, Nov 13 '20 at 02:47

score 0 · Accepted Answer · answered Nov 13 '20 at 02:48

This should work directly :

df[df$years > 0, 13:100] <- NA

Consider this small example :

set.seed(123)
df <- data.frame(years = c(-1, 1, -3, -4, 9), var1 = rnorm(5), var2 = rnorm(5))
df

#  years        var1       var2
#1    -1 -0.56047565  1.7150650
#2     1 -0.23017749  0.4609162
#3    -3  1.55870831 -1.2650612
#4    -4  0.07050839 -0.6868529
#5     9  0.12928774 -0.4456620
df[df$years > 0, 2:3] <- NA
df

#  years        var1       var2
#1    -1 -0.56047565  1.7150650
#2     1          NA         NA
#3    -3  1.55870831 -1.2650612
#4    -4  0.07050839 -0.6868529
#5     9          NA         NA

this solution worked! Thank you so much. – rookie11 Nov 13 '20 at 03:35 — rookie11, Nov 13 '20 at 03:35

For loop to replace values with NA based on a condition in R

1 Answers1