not having to load a dataset over and over
It depends how large your data set is. 
For relatively smaller datasets you could look at installing Anaconda Python Jupyter notebooks. Really great for working with data and visualisation once the dataset is loaded. For larger datasets you can write some functions / generators to iterate efficiently through the dataset.
Currently in R, once you load a dataset (for example with read.csv), Rstudio saves it as a variable in the global environment. This ensures you don't have to load the dataset every single time you do a particular test or change. 
With Python, I do not know which text editor/IDE will allow me to do this. E.G - I want to load a dataset once, and then subsequently do all sorts of things with it, instead of having to load it every time I run the script. 
Any points as to how to do this would be very useful