R言語　if_elseの挙動について ex > ex > name score test rank > 1 john 80 0 4 > 2 taro 60 0 3 > 3 betty 70 NA 2 > 4 hanako 50 0 1 testNArankNA > mutate(ex,rank = if_else(test == 0,true = rank,false = NA)) > mutate(ex,rank = if_else(test == 0,true = rank,false = 0))

`dplyr::if_else()` `true` `false`
rank `NA``NA_real_`

`mutate(ex, rank = if_else(test == 0, true = rank, false = NA_real_))`



> testNArankNA




mutate(ex, rank = if_else(is.na(test), true = NA_real_, false = rank))
#> # A tibble: 4 x 4
#> name score test rank
#>
#> 1 john 80 0 4
#> 2 taro 60 0 3
#> 3 betty 70 NA NA
#> 4 hanako 50 0 1