List handling in python

Python: 3.7.6 Pycharm 2020.3.3

Flatten 2D list to 1D (flatten_list.py)

Flatten the data(merge data) in 2D list to 1D list. code has 10 methods to flatten the data. Method 8 can also flatten 3D list to 1D. Different data type/format data can also be flattened by method 8 All code are merged in code (flatten_list_mtds_all.py), for that install package perfplot(pip install perfplot==0.10.2)