CSV Column Compare

Lists the elements of one column (left), which are not in another (right), across two CSVs

Pure Python (s/b 2.7, +3.5)
Column or 0-index based header selection
Easy to tweak the reader or it's options (delimiter, escape, etc.)
Ignores case and padding (via .lower() and .strip())
Single File
In-RAM
Output is sorted alphabetically
Output is de-duplicated

... and no testing, license or warranty of any kind!

Usage

wget https://raw.githubusercontent.com/jnmclarty/csvcolcmp/master/main.py
python main.py left.csv some_col right.csv other_col > left_not_in_right.csv