4 ms·

1^NA is 1, and 2^NA is NA. Bizarre!

by nomilk 5y ago

fithisux 5y ago
R has many cases of inconsistency. Like substitute "its value is substituted, unless env is .GlobalEnv in which case the symbol is left unchanged." dim and dims :-) R could do more here. I really like R.
- nomilk 5y ago
  Interesting. I must admit I've never used substitute. I tried dims but: Error in dims(iris) : could not find function "dims" I do find the occasional oddity. I've noticed more very useful messages/warnings (particularly in common tidyverse functions) recently, so I think they help. To be fair, these quirks are generally very uncommon in day to day use.
- nojito 5y ago
  You may want to check out substitute2 which is much easier to use. https://rdatatable.gitlab.io/data.table/reference/substitute2.html https://rdatatable.gitlab.io/data.table/reference/substitute...
sin7 5y ago
1*0 = 1 1*1 = 1 1*-1 = 1 2*0 = 1 2*1 = 2 2*-1 = 1/2 When 1 raised to any power equals 1, does the power matter at all? Even if it's unknown, the answer is 1.
- nomilk 5y ago
  Good point. Although if NA were complex: 1^1+0i is 1+0i.
  - _fnhr 5y ago
    There are different NAs for different types of objects. And that's why you get: 1^NA_complex_ # NA But: 1^NA_real_ # 1
nosianu 5y ago
It works and is IMO quite okay because NA is not the same as NaN (not a number). NA _does_ actually stand for a number, it's just that we don't know it. Which is an interesting detail in R that should be mentioned anyway, the difference between NA and NaN. Anyone used to languages which just NaN may confuse NA for that non-value. https://www.r-bloggers.com/2012/08/difference-between-na-and-nan-in-r/ https://www.r-bloggers.com/2012/08/difference-between-na-and... https://cran.r-project.org/doc/manuals/r-release/R-lang.html#NA-handling https://cran.r-project.org/doc/manuals/r-release/R-lang.html... (lots of details how NA and NaN are handled) Except - 1^NaN also is 1... now that IMO is wrong. But you can try the same in your browser's JS console and you will get 1 as a result too, so R is not the only one. There are several NA values in R - NA_integer_, NA_real_, NA_complex_ and NA_character_, and the results will be different if you use some of them. NA_character_ and NA_complex_ will produce errors (different ones).
- _fnhr 5y ago
  Agree about 1^NaN being strange. Also R's cleverness with NA's is not so consistent. For example: median(c(1,1,1,NA)) Should return 1, since no matter what value is behind NA the median is still 1. But it returns NA.

1^NA is 1, and 2^NA is NA. Bizarre!

by nomilk 5y ago

1^NA is 1, and 2^NA is NA. Bizarre!

R has many cases of inconsistency. Like substitute "its value is substituted, unless env is .GlobalEnv in which case the symbol is left unchanged." dim and dims :-) R could do more here. I really like R.

nomilk 5y ago
Interesting. I must admit I've never used substitute. I tried dims but: Error in dims(iris) : could not find function "dims" I do find the occasional oddity. I've noticed more very useful messages/warnings (particularly in common tidyverse functions) recently, so I think they help. To be fair, these quirks are generally very uncommon in day to day use.
nojito 5y ago
You may want to check out substitute2 which is much easier to use. https://rdatatable.gitlab.io/data.table/reference/substitute2.html https://rdatatable.gitlab.io/data.table/reference/substitute...

sin7 5y ago

1*0 = 1 1*1 = 1 1*-1 = 1 2*0 = 1 2*1 = 2 2*-1 = 1/2 When 1 raised to any power equals 1, does the power matter at all? Even if it's unknown, the answer is 1.

nomilk 5y ago
Good point. Although if NA were complex: 1^1+0i is 1+0i.
- _fnhr 5y ago
  There are different NAs for different types of objects. And that's why you get: 1^NA_complex_ # NA But: 1^NA_real_ # 1

nosianu 5y ago

It works and is IMO quite okay because NA is not the same as NaN (not a number). NA _does_ actually stand for a number, it's just that we don't know it. Which is an interesting detail in R that should be mentioned anyway, the difference between NA and NaN. Anyone used to languages which just NaN may confuse NA for that non-value. https://www.r-bloggers.com/2012/08/difference-between-na-and-nan-in-r/ https://www.r-bloggers.com/2012/08/difference-between-na-and... https://cran.r-project.org/doc/manuals/r-release/R-lang.html#NA-handling https://cran.r-project.org/doc/manuals/r-release/R-lang.html... (lots of details how NA and NaN are handled) Except - 1^NaN also is 1... now that IMO is wrong. But you can try the same in your browser's JS console and you will get 1 as a result too, so R is not the only one. There are several NA values in R - NA_integer_, NA_real_, NA_complex_ and NA_character_, and the results will be different if you use some of them. NA_character_ and NA_complex_ will produce errors (different ones).

_fnhr 5y ago
Agree about 1^NaN being strange. Also R's cleverness with NA's is not so consistent. For example: median(c(1,1,1,NA)) Should return 1, since no matter what value is behind NA the median is still 1. But it returns NA.