Why does plot funtion not recognize my categorial data?

[Susanne]

Sorry for a probably stupid question from a beginner:

In my data set I want to plot categorial data (three classes of medication) versus quantitative data (qPCR), but plot () does not recognize the medication.
It works perfectly fine with the dataset head "(iris) from the R-tutorial". Therefore the code is correct per se.

I defined medication from the uploaded filenames ( e.g. 2020_02_04_M533mtx_Mepo_bevor_PCRplate_1.txt) by using: med <- substr(x, 20, nchar(x).
Mepo is the medication here.
How can I tell R Studio that this is ot just a name but a variable?
Thannk you in advance for help!

[andresrcs]

Hi!

To help us help you, could you please prepare a reproducible example (reprex) illustrating your issue? Please have a look at this guide, to see how to create one:

FAQ: How to do a minimal reproducible example ( reprex ) for beginners

A minimal reproducible example consists of the following items: A minimal dataset, necessary to reproduce the issue The minimal runnable code necessary to reproduce the issue, which can be run on the given dataset, and including the necessary information on the used packages. Let's quickly go over each one of these with examples: Minimal Dataset (Sample Data) You need to provide a data frame that is small enough to be (reasonably) pasted on a post, but big enough to reproduce your issue. Let's say, as an example, that you are working with the iris data frame head(iris) #> Sepal.Length Sepal.Width Petal.Length Petal.Width Species #> 1 5.1 3.5 1.4 0.…

[Susanne]

Thank you - I finally solved the problem (after 2 days).
R "saw" my data as characters: final_data$med <- as.factor(final_data$med) did the job.
Apologies for having disturbed you!
Actually it had already workd in the iris data frame but not in mine