I have these four lists, which are the filenames of images and the filenames are in the format:

(disease)-(randomized patient ID)-(image number by this patient)

A single patient can have multiple images per disease.

See these slices below:

```
print(train_cnv_list[0:3])
print(train_dme_list[0:3])
print(train_drusen_list[0:3])
print(train_normal_list[0:3])
>>>
['CNV-9911627-77.jpeg', 'CNV-9935363-45.jpeg', 'CNV-9911627-94.jpeg']
['DME-8889850-2.jpeg', 'DME-8773471-3.jpeg', 'DME-8797076-11.jpeg']
['DRUSEN-8986660-50.jpeg', 'DRUSEN-9100857-3.jpeg', 'DRUSEN-9025088-5.jpeg']
['NORMAL-9490249-31.jpeg', 'NORMAL-9509694-5.jpeg', 'NORMAL-9504376-3.jpeg']

```

I'd like to figure out:

1. How many images are there per patient / per list?
2. Is there any overlap in the "randomized patient ID" across the four lists? If so, can I aggregate that into some kind of report (patient, disease, number of images) using something like groupby?

```
patient - disease1 - total number of images

        - disease2 - total number of images

        - disease3 - total number of images

```

where total number of images is a max(image number by this patient)

I did see that this yields a patient id:

```
train_cnv_list[0][4:11]
>>> 9911627

```

Thanks, in advance, for any guidance.