[R] unexpected 'else' in " else"

[Jinsong Zhao]

Thanks a lot!

I know the first and third way to correct the error. The second way 
seems make me know why the code is correct in the function 
stats::weighted.residuals.

On 2022/10/21 17:36, Andrew Simmons wrote:
> The error comes from the expression not being wrapped with braces. You 
> could change it to
>
> if (is.matrix(r)) {
>     r[w != 0, , drop = FALSE]
> } else r[w != 0]
>
> or
>
> {
>     if (is.matrix(r))
>         r[w != 0, , drop = FALSE]
>     else r[w != 0]
> }
>
> or
>
> if (is.matrix(r)) r[w != 0, , drop = FALSE] else r[w != 0]
>
>
> On Fri., Oct. 21, 2022, 05:29 Jinsong Zhao, <jszhao using yeah.net> wrote:
>
>     Hi there,
>
>     The following code would cause R error:
>
>      > w <- 1:5
>      > r <- 1:5
>      >         if (is.matrix(r))
>     +             r[w != 0, , drop = FALSE]
>      >         else r[w != 0]
>     Error: unexpected 'else' in "        else"
>
>     However, the code:
>              if (is.matrix(r))
>                  r[w != 0, , drop = FALSE]
>              else r[w != 0]
>     is extracted from stats::weighted.residuals.
>
>     My question is why the code in the function does not cause error?
>
>     Best,
>     Jinsong
>
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