course/r4ds
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Expand a bit on Boolean + missing, closes #1454

Browse Source
This commit is contained in:
mine-cetinkaya-rundel
2023-05-09 22:57:02 -04:00
parent c2b0451044
commit 35a806d9ed
1 changed files with 4 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
logicals.qmd
View File

@@ -243,9 +243,11 @@ df |>
) )
``` ```
To understand what's going on, think about `NA | TRUE`. To understand what's going on, think about `NA | TRUE` (`NA` or `TRUE`).
A missing value in a logical vector means that the value could either be `TRUE` or `FALSE`. A missing value in a logical vector means that the value could either be `TRUE` or `FALSE`.
`TRUE | TRUE` and `FALSE | TRUE` are both `TRUE`, so `NA | TRUE` must also be `TRUE`. `TRUE | TRUE` and `FALSE | TRUE` are both `TRUE` because at least one of them is `TRUE`.
`NA | TRUE` must also be `TRUE` because `NA` can either be `TRUE` or `FALSE`.
However, `NA | FALSE` is `NA` because we don't know if `NA` is `TRUE` or `FALSE`.
Similar reasoning applies with `NA & FALSE`. Similar reasoning applies with `NA & FALSE`.
### Order of operations ### Order of operations