Error in QS scraping if metrics blank

Errors occurring in QS scrape for some combinations of subjects and years.

Appears to be occurring where some Ranking Indicators rankings show as '-' on QS world rankings website.

Example from 2018 Arts and Design (see ranking on website https://www.topuniversities.com/university-rankings/university-subject-rankings/2018/art-design)

ur_scrape_qs(2018, ranking="Art.Design")

Returns:

Error: Unknown columns `2626624`, `2626624_rank_d`, `2626624_rank`, `2626625`, `2626625_rank_d` and `2626625_rank` 
Call `rlang::last_error()` to see a backtrace

Error appears to occur because data returned by JSON is missing above columns so code that links data and column names fails (further investigation required).

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information