[R] Applying by() when groups have different lengths [RESOLVED]

[Rich Shepard]

On Mon, 17 Sep 2018, MacQueen, Don wrote:

> I'm also going to guess that maybe your object rainfall_by_site has
> already been split into separate data frames (because of its name). But
> by() does the splitting internally, so you should be passing it the
> original unsplit data frame.

Don,

   I did not pick up on by() doing the splitting for me when I read the help
file and a few web sites!

   Using the unsplit data.frame did the job; e.g.,

rainfall[, "name"]: Sandy 1.4 NE
[1] 0.1636066
------------------------------------------------------------ 
rainfall[, "name"]: Sandy 1.7 SSW
[1] 0.2021324
------------------------------------------------------------ 
rainfall[, "name"]: Sherwood 3.3 SE
[1] 0.1461752

   Now I know how to properly apply by() to an unsplit dataframe. Thanks for
the insightful lesson.

Best regards,

Rich