up vote 148 down vote favorite
230

Hi all,

I've been learning, working, and playing with Python for a year and a half now. As a biologist slowly making the turn to bio-informatics, this language has been a the very core of all the major contributions I have made in the lab. I more or less fell in love with the way Python permits me to express beautiful solutions and also with the semantics of the language that allows such a natural flow from thoughts to workable code.

What I would like to know is your answer to a kind of question I have seldom seen in this or other forums. This question seems central to me for anyone on the path to Python improvement but who wonders what his next steps should be.

Let me sum up what I do NOT want to ask first ;)

  • I don't want to know how to QUICKLY learn Python
  • Nor do I want to find out the best way to get acquainted with the language
  • Finally, I don't want to know a 'one trick that does it all' approach.

What I do want to know your opinion about, is:

What are the steps YOU would recommend to a Python journeyman, from apprenticeship to guru status (feel free to stop wherever your expertise dictates it), in order that one IMPROVES CONSTANTLY, becoming a better and better Python coder, one step at a time. Some of the people on SO almost seem worthy of worship for their Python prowess, please enlighten us :)

The kind of answers I would enjoy (but feel free to surprise the readership :P ), is formatted more or less like this:

  • Read this (eg: python tutorial), pay attention to that kind of details
  • Code for so manytime/problems/lines of code
  • Then, read this (eg: this or that book), but this time, pay attention to this
  • Tackle a few real-life problems
  • Then, proceed to reading Y.
  • Be sure to grasp these concepts
  • Code for X time
  • Come back to such and such basics or move further to...
  • (you get the point :)

I really care about knowing your opinion on what exactly one should pay attention to, at various stages, in order to progress CONSTANTLY (with due efforts, of course). If you come from a specific field of expertise, discuss the path you see as appropriate in this field.

EDIT: Thanks to your great input, I'm back on the Python improvement track! I really appreciate!

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13  
i don't feel qualified to answer this but am looking forward to the responses. GREAT QUESTION – Tom Willis Apr 4 at 2:25
I asked a similar question some time ago: stackoverflow.com/questions/29578/… – Jiaaro 13 hours ago
Love you for this question. I was a frog in the well. This question just gave me a ladder to get out.. – Keerthi Ramalingam 7 hours ago

16 Answers

up vote 107 down vote accepted

I thought the process of Python mastery went something like:

  1. Discover list comprehensions
  2. Discover generators
  3. Incorporate map, reduce, filter, iter, range, xrange often into your code
  4. Discover Decorators
  5. Write recursive functions, a lot
  6. Discover itertools and functools
  7. Read Real World Haskell
  8. Rewrite all your old Python code with tons of higher order functions, recursion, and whatnot.
  9. Annoy your cubicle mates every time they present you with a Python class. Claim it could be "better" implemented as a dictionary plus some functions. Embrace functional programming.
  10. Rediscover the Strategy pattern and then all those things from imperative code you tried so hard to forget after Haskell.
  11. Find a balance.
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+1 for giving more reasons to head over to Real World Haskell. – jeffjose Apr 5 at 10:26
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Yes and no. I find I write better and more concise code the closer I get to functional programming. That said, there are plenty of places where things are expressed more clearly in an imperative manner. There's a reason Real World Haskell is sold out at Python conventions, it makes you a better programmer. My advice, explore as many facets of Python as you can, then try a functional language. – wheaties Apr 5 at 13:32
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@wheatis I'm now scared if I read into Haskell I'll abandon Python for good. – Beau Martínez Apr 10 at 2:16
1  
Beginners: Dictionary then later on... Mastery: Metaprogramming – gath Apr 16 at 14:25
1  
Can i heartily recommend Dive Into Python as a way of doing #1, 2, 3, and 4? That book helped me tons – Claudiu Oct 4 at 17:21
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up vote 38 down vote

One good way to further your Python knowledge is to dig into the source code of the libraries, platforms, and frameworks you use already.

For example if you're building a site on Django, many questions that might stump you can be answered by looking at how Django implements the feature in question.

This way you'll continue to pick up new idioms, coding styles, and Python tricks. (Some will be good and some will be bad.)

And when you see something Pythony that you don't understand in the source, hop over to the #python IRC channel and you'll find plenty of "language lawyers" happy to explain.

An accumulation of these little clarifications over years leads to a much deeper understanding of the language and all of its ins and outs.

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+1 for "read other people's code, frequently" – FogleBird Apr 4 at 1:19
@dkamins Thanks for the advices. Sure will dig into specific libraries (for me, that would be Biopython). I wasn't aware of the #python IRC channel. Will also give it a try. :) – Morlock Apr 4 at 3:57
I would add to this that instead of simply installing a django extension/plugin, try adding the code manually using a git branch. This will force you to actually read the code you are adding to the project. – Noah Apr 11 at 3:21
up vote 27 down vote

Understand (more deeply) Python's data types and their roles with regards to memory mgmt

As some of you in the community are aware, I teach Python courses, the most popular ones being the comprehensive Intro+Intermediate course as well as an "advanced" course which introduces a variety of areas of application development.

Quite often, I get asked a question quite similar to, "Should I take your intro or advanced course? I've already been programming Python for 1-2 years, and I think the intro one is too simple for me so I'd like to jump straight to the advanced... which course would you recommend?"

To answer their question, I probe to see how strong they are in this area -- not that it's really the best way to measure whether they're ready for any advanced course, but to see how well their basic knowledge is of Python's objects and memory model, which is a cause of many Python bugs written by those who are not only beginners but those who have gone beyond that.

To do this, I point them at this simple 2-part quiz question: Ex1: x=42; y=x; x+=1; print x,y Ex2: x=[1,2,3];y=x;x[0]=4;print x,y

Many times, they are able to get the output, but the why is more difficult and much more important of an response... I would weigh the output as 20% of the answer while the "why" gets 80% credit. If they can't get the why, regardless how Python experience they have, I will always steer people to the comprehensive intro+intermediate course because I spend one lecture on objects and memory management to the point where you should be able to answer with the output and the why with sufficient confidence. (Just because you know Python's syntax after 1-2 years doesn't make you ready to move beyond a "beginner" label until you have a much better understanding as far as how Python works under the covers.)

A succeeding inquiry requiring a similar answer is even tougher, e.g.,

Example 3

x = ['foo', [1,2,3], 10.4]
y
= list(x) # or x[:]
y
[0] = 'fooooooo'
y
[1][0] = 4
print x
print y

The next topics I recommend are to understanding reference counting well, learning what "interning" means (but not necessarily using it), learning about shallow and deep copies (as in Example 3 above), and finally, the interrelationships between the various types and constructs in the language, i.e. lists vs. tuples, dicts vs. sets, list comprehensions vs. generator expressions, iterators vs. generators, etc.; however all those other suggestions are another post for another time. Hope this helps in the meantime! :-)

ps. I agree with the other responses for getting more intimate with introspection as well as studying other projects' source code and add a strong "+1" to both suggestions!

pps. Great question BTW. I wish I was smart enough in the beginning to have asked something like this, but that was a long time ago, and now I'm trying to help others with my many years of full-time Python programming!!

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Wesley Chun! Morlock, this is the kind of guy you were talking about in the bolded part of your question. A deeply knowledgable guy who also a very gifted teacher, I got a huge boost from the book. – bvmou Apr 5 at 19:11
thx @bvmou! i could only answer this question because i had to go through this learning process like everyone else... only mine was 13 years ago! :-) thx for plugging corepython.com tho! :-) – wescpy Apr 9 at 4:53
up vote 21 down vote

Understand Introspection

  • write a dir() equivalent
  • write a type() equivalent
  • figure out how to "monkey-patch"
  • use the dis module to see how various language constructs work

Doing these things will

  • give you some good theoretical knowledge about how python is implemented
  • give you some good practical experience in lower-level programming
  • give you a good intuitive feel for python data structures
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Nice suggestions. Added to my Python todo list! – Morlock Apr 4 at 13:57