[R] Problem with creating a PCA graph in a loop

[Gavin Duley]

> On 8 May 2024, at 09:16, Ivan Krylov <ikrylov using disroot.org> wrote:
> 
> В Tue, 7 May 2024 16:57:14 +0200
> gavin duley <gduley using gmail.com> пишет:
> 
>> aes(label=current_rownames,
>>    colour=wine.data.filt$Treatment
>> )
> 
> As you've noticed, aes() remembers variables by their name and
> environment, not by value:

Yes, it was something I wasn’t aware of previously. I thought once I’d created a ggplot object, it was fairly static/unchanging.

That this is limited to aes() explains why the title set using ggtitle isn’t affected in the same way — thanks!

> One way to get around the problem is to ensure that the variables live
> in different environments. Instead of making it a for loop, write a
> function that would accept `i` and return a plot instead of assigning
> it by name:

Thanks, that does seem like a good option. I’m less familiar with writing functions, but it’s something I’m trying to learn about. I’ll try it and see how it goes.

> (In many languages, trying to use a variable as a variable name, while
> possible, usually means you need to consider some kind of nested data
> structure:
> https://perldoc.perl.org/perlfaq7#How-can-I-use-a-variable-as-a-variable-name?
> In R, this structure is a list.)

Ok, that’s useful to know, thanks. I don’t really have much programming experience beyond R, so there’s a lot I don’t know.

> Alternatively, supply a data= argument to geom_label_repel() and make
> your mapping = aes(...) reference variables from the data (which will
> be remembered), ignoring the environment (which is only referenced).
> Something like the following should work, untested:


Thanks, I’ll try that out too.

Many thanks for giving me a few suggestions. I was completely stuck, but these have given me a few good things to try!

Thanks,
gavin,