Personally, I always use ipython. I have ipython aliased to "I" in every OS and my preamble/startup environment contains from numpy import * from numpy

Personally, I always use ipython. I have ipython aliased to "I" in every OS and my preamble/startup environment contains from numpy import * from numpy import array as c from math import * import numpy as np import pandas as pd import matplotlib.pyplot as plt Previously I used to use R, which also has a very fast REPL with self-documentation similara to ipython's '?' magic.