r - When trying to replace values, "missing values are not allowed in subscripted assignments of data frames"

Question

I have a table that has two columns: whether you were sick (H01) and the number of days sick (H03). However, the number of days sick is NA if H01 == false, and I would like to set it to 0. When I do this:

test <- pe94.person[pe94.person$H01 == 12,]
test$H03 <- 0

It works fine. However, I'd like to replace the values in the original dataframe. This, however, fails:

pe94.person[pe94.person$H01 == 12,]$H03 <- 0

It returns:

> pe94.person[pe94.person$H01 == 12,]$H03 <- 0
Error in `[<-.data.frame`(`*tmp*`, pe94.person$H01 == 12, , value = list( : 
  missing values are not allowed in subscripted assignments of data frames

Any idea why this is? For what it's worth, here's a frequency table:

> table(pe94.person[pe94.person$H01 == 12,]$H03)

 2  3  5 28 
 3  1  1  1 

question from:https://stackoverflow.com/questions/23396279/when-trying-to-replace-values-missing-values-are-not-allowed-in-subscripted-as

Answer 1

You can use ifelse, like so

pe94.person$foo <- ifelse(!is.na(pe94.person$H01) & pe94.person$H01 == 12, 0, pe94.person$H03)

check if foo meets your criteria and then go ahead and assign it to pe94.person$H03 directly. I find it safer to assign it a new variable and usually use that in subsequent analysis.