What is the difference between list and tuples?
Lists are mutable i.e they can be edited. Tuples are immutable (tuples are lists which can’t be edited)
If you split your data into train/test splits, is it still possible to overfit your model?
Yes, it's definitely possible. One common beginner mistake is re-tuning a model or training new models with different parameters after seeing its performance on the test set. In this case, its the model selection process that causes the overfitting. The test set should not be tainted until you're ready to make your final selection.
Swap the values of two variables "a" and "b", without using a third variable.
a= a+b; b = a-b; a = a-b;