Wait, don’t answer that. It doesn’t matter.
Beginners seem to ask this question when they are feeling daunted by the challenge before them. Maybe they are hoping for a helpful answer, but it seems like most answers will just be a jumping off point for feeling bad about their own progress.
Everyone learns differently. They learn from different sources, at different paces. Suppose you ask this question and someone answers “one month”? Will you feel bad about yourself because you’ve been at it for six weeks? Suppose they say, “ten years”? Now what do you think?
The question doesn’t even make sense in a way. What do we mean by “learn”? If you can write a number guessing game in Python, have you learned Python? Are we talking about basic familiarity, or deep memorization? Does something have to be second nature, or is it OK if you are still looking through the docs for details? “Learned” is not a binary state. There isn’t a moment where you don’t know Python, and then suddenly you do.
And what do we even mean by “Python”? Are we talking about the basic syntax, or do you need to be able to write a metaclass, a descriptor, and a decorator with arguments? Is it just the language, or also the standard library? How many of the 200+ modules in the standard library do you need to be familiar with? What about commonly used third-party libraries? Are we also including the skills needed to write large (10k lines) programs in Python? “Python” is a large and varied landscape, and you will be finding out new things about it for years and years.
Especially since it keeps changing! Python isn’t sitting still, so you will never be done “learning Python.” I have been using Python for more than 20 years, and been deeply involved with it for at least half that time. I thought I knew Python well, then they added “async”. I will have to figure that out one of these days...
Since Python is used in many different domains, the things you need to learn could be completely different from someone else. These days, lots of people are learning Python to get into data science. I don’t do data science. Here are more things I don’t know (taken from a random sampling of “libraries you should know” blog posts): TensorFlow, Scikit-Learn, Numpy, Keras, PyTorch, SciPy, Pandas, Matplotlib, Theano, NLTK, etc. How should I compare my learning to a data scientist’s?
My advice to beginners is: don’t compare your learning to other peoples’. Everyone learns differently, using different materials, at different speeds. Everyone has different definitions of “learn,” and of “Python.” Understand your goals and your learning style. Find materials that work for you. Study, and learn in your own way. You can do it.