CODEWITHSUNDEEP
rif-statementmissing-data
student_R123
student_R123

Reputation: 1002

if else with missing observations in R

Lets say I have following 2 variables

z1=c(0,1,1,0,NA,1,0,NA ,1)
z2=c(0,1,0,NA,1,0,0,0,NA)

So the both variables has missing values. I need to create a new variable Z as follows,

Z=1 if at least one of the variables (z1 and z2) are equal to 1.(following situations z1=1 & z2=1 , z1=0 & z2=1 ,z1=1 & z2=0 , z1=1 & z2=NA , z1=NA & z2=1)

Z=0 if at least one of the variables(z1 and z2) are equal to 0.(following situations z1=0 & z2=0 , z1=0 & z2=NA ,z1=NA & z2=0 )

So i performed the following nested ifelse statement and got this output,

     ifelse(z1==1|z2==1,1,ifelse((z1==0|z2==0),0 ,0))
  0  1  1 NA  1  1  0 NA  1

there seems to be something wrong with my if-else statement as my ideal output should be something like this,

0  1  1 0  1  1  0 0  1

can any one help me to figure out what is incorrect in my code ?

Thank you

Upvotes: 1

Views: 292

Answers (2)

tomasu
tomasu

Reputation: 1438

I believe coalesce() in the dplyr packages accomplishes your desired output:

library(dplyr)

coalesce(z1, z2)
[1] 0 1 1 0 1 1 0 0 1

If you are looking to perhaps append the new values to your previous:

df <- tibble(
  z1 = c(0, 1, 1, 0, NA, 1, 0, NA, 1),
  z2 = c(0, 1, 0, NA, 1, 0, 0, 0, NA)
)

df %>% 
  mutate(z3 = coalesce(z1, z2))

# A tibble: 9 x 3
     z1    z2    z3
  <dbl> <dbl> <dbl>
1     0     0     0
2     1     1     1
3     1     0     1
4     0    NA     0
5    NA     1     1
6     1     0     1
7     0     0     0
8    NA     0     0
9     1    NA     1

Upvotes: 1

akrun
akrun

Reputation: 886938

We can use pmax with na.rm as TRUE

pmax(z1, z2, na.rm = TRUE)
#[1] 0 1 1 0 1 1 0 0 1

Upvotes: 3

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