My question is how can I create a tibble or data frame which should look like the following:
So the JEL codes should be grouped by letters, by letters and first number and then per letter and two numbers. Util now I was not able to extract the letters out of JEL_codes, because it is a list and when I do extract it this list is longer than the list of the volumes and I cant create a tibble anymore.
At the moment I have tibble that looks like this where I got observations of JEL_codes and the volume:
Maybe as a first step I would seperate the observations so that one JEL code matches with a volume , so no thwo JEL codes are in a row. Anything that brings me a little bit further helps me, thank you a lot!