December 2013

My Brief Coding History

13 years ago, I fell in love with Perl. I liked Perl a lot better than my previous flings with HTML, Shell (Bash), PHP, ASP, Javascript, Sed, Awk and a few others, mainly because Perl was always willing to do what I wanted, when I wanted, making my life as a Sys Admin a lot easier and never asked much in return just to be loved. I loved Perl for years and years and in a way I will never stop loving Perl, after all Perl was my first love. But too often our first loves die hard no matter how hard we try to will their existence forward…

“I never thought I could love a language more than Perl, until I met Python”  (TuxNinja, 2012)

Enter Python

Old loves die hard.. I haven’t used Perl for about ~18 months, whatever the exact amount of time is I am not sure, but it matches the exact time at which I started learning Python.  I decided to start learning Python because it’s popularity seemed to be growing exponentially (and still does), once I learned basic syntax by reading and watching a couple of videos, I was up and running and it wasn’t long before I was solving real business critical problems with it.

[stextbox id=”grey” caption=”Best Way To Learn A New Language”]I have learned a lot of languages. By far the best way to learn a new language is to solve a real problem (preferably at your job) with it. The reason being is that inevitably when you solve the problem you will need to maintain the code (i.e. add features and fix bugs). This ‘recall’ you experience every time you re-visit and re-factor your code will burn into your brain valuable learning’s better than any amount of writing and/or reading alone. Suffices to say that troubleshooting is the best way to learn.[/stextbox]

Two Reasons

There were two major reasons once I started learning Python I decided it was my new #1.

1. Python is the most readable language I have ever seen. It reads like pseudo code or plain english. If that isn’t important to you, go try to read someones competition winning obfuscated code ./facepalm. For the 13 years I coded Perl every time I took over a Perl script from someone else I re-wrote it. That is because Perl allows for coders to follow many different styles such as a C or Shell style of coding. It’s flexibility is it’s greatest enemy in my opinion, there are 1000 ways to do something in Perl. In Python there are 10’s of ways, but there is usually only 1 pythonic way. I prefer a language that has a clear best way to do something and that encourages readability. Of course there are still some assholes out there who prefer lambda() and map() over list comprehension and to them I say… read a book (err website)
2. Community support. I forever loved Perl. Two of the reasons was the incredible support I found on www.perlmonks.com and because of CPAN and the plethra of modules that existed. Well Python wins again. It’s seems most former monks now spend their time correcting peoples Python on StackOverflow.com and PyPi > CPAN, sorry but it’s true !

All that being said, I encourage you to learn Python, Ruby, and Node.js… these 3 seem to be the front runners of that the next generation is learning and therefore will continue to be abound now and in the future. But since this is a Python article and the language I know best, learn Python first !

CheckIO

Finally, the purpose of this article! About 3 months into learning Python a good friend of mine who is a programmer for a living told me about CheckIO.org, which is a website, that provides a fun & free way to learn Python in the form of a game that reminds me of Wii’s Super Mario. Now when I initially signed up ~15 months ago I never actually ended up playing the game. Until a couple of days ago when I got an email from them asking how I liked CheckIO. Well that was all the reminder I needed, looking to continue in life long learning and specifically my Python knowledge I started playing the game. It’s been 48 hours and I am pretty hooked ! The benefits to learning using CheckIO are unmatched by any other learning mechanisms I have used to date here’s why.

How It Works

CheckIO starts you at your ‘home’ and presents you with challenges that it gives you points and badges for completing. Once you complete enough you move on to the next challenge and eventually unlock other adventures and your next set of challenges. Yea, yea ok that’s cool so what…well when you solve your challenge, you have the option of publishing your code and reviewing / voting on the best solution of all time for that problem. This is an amazing thing. It combines not only exercising to solve a problem yourself, but ultimately showing you the most clean, efficient and pythonic way (caveat: not always but mostly the social voting keeps this true). This is an incredible about of knowledge in one place, and the challenges you are solving are universally applicable to some of the most common problems with data structures, sorting and counting that you will run into. Admittedly, I am a level 4 currently and only about 60% of the way through and have already unlocked other adventures, but I was having so much fun and learning so much that I decided I’m going to complete 100% of an adventure before moving on.

CheckIO Teaches You To Be An Efficient Programmer

Feel free to read that again. Yes it does. My whole programming life I have been focused on function…function, function, function. Making my code functional was always #1 because after all you are solving a problem and making your code functional has to be the right first step anyway, you can’t work on making an application efficient if you haven’t figured out a way to solve the problem programmaticly. So the only time I went back and re-wrote an program to make it more efficient was when it was heavily used so incredibly inefficient that it demanded to be FIXED!

Let There Be Light

What CheckIO does is encourages you to compete with other programmers solving the same challenges in the game format, keeping it fun. So finally 6 challenges in, I started to get it… instead of just solving the challenge, why not try to solve the challenge in the most efficient & cleanest way possible and then publish my code for voting with the community. I did just that and the difference in my code was a difference of 47 lines.  The example I am showing below is a basic one, but the story is what’s crucial. If you solve the CheckIO problems and challenge yourself to write the best possible solution each time and then compare against your peers you will ultimately be a far better programmer then most people. Not to mention you will have a nice repository for re-usable code for common problems you will encounter as a programmer.

Ok enough…it’s show and tell time.

The Problem

Full Problem Description: http://www.checkio.org/mission/roman-numerals/
Short Version: For this task, you should return a roman numeral using the specified integer value ranging from 1 to 3999.

Input: An integer ranging from 1 to 3999.
Output: A string in the form of a Roman numeral.
Example:

checkio(6) == 'VI'
checkio(76) == 'LXXVI'

Functional Solution

import random

numerals = { 1 : 'I', 4 : 'IV', 5 : 'V', 9 : 'IX', 10 : 'X', 40 : 'XL', 50 : 'L', 90 : 'XC', 100 : 'C', 400 : 'CD', 500 : 'D', 900 : 'CM', 1000 : 'M' }
number = random.randrange(4000)
string = ''

if (number / 1000):
    thousands = number / 1000 # thousands
    string += numerals[1000]*thousands
    number = number - (thousands*1000)
if (number / 900):
    ninehundreds = number / 900 # 900's
    string += numerals[900]*ninehundreds
    number = number - (ninehundreds*900)
if (number / 500):
    fivehundreds = number / 500 # 500's
    string += numerals[500]*fivehundreds
    number = number - (fivehundreds*500)
if (number / 400):
    fourhundreds = number / 400 # 400's
    string += numerals[400]*fourhundreds
    number = number - (fourhundreds*400)
if (number / 100):
    hundreds = number / 100 # 100's
    string += numerals[100]*hundreds
    number = number - (hundreds*100)
if (number / 90):
    nineties = number / 90 # 90's
    string += numerals[90]*nineties
    number = number - (nineties*90)
if (number / 50):
    fifties = number / 50 # 50's
    string += numerals[50]*fifties
    number = number - (fifties*50)
if (number / 40):
    forties = number / 40 # 40's
    string += numerals[40]*forties
    number = number - (forties*40)
if (number / 10):
    tens =  number / 10 # 10's
    string += numerals[10]*tens
    number = number - (tens*10)
if (number / 9):
    nines =  number / 9 # 9's
    string += numerals[9]*nines
    number = number - (nines*9)
if (number / 5):
    fives = number / 5 # 5's
    string += numerals[5]*fives
    number = number - (fives*5)
if (number / 4):
    fours = number / 4 # 4's
    string += numerals[4]*fours
    number = number - (fours*4)
if (number / 1):
    ones = number / 1 # 1's
    string += numerals[1]*ones
    number = number - (ones*1)

print string

My Think Twice Solution

It’s amazing how quickly you can improve code once you understand how it needs to function. This improvement took me a total of 2 minutes to finish.

import random

numerals = { 1 : 'I', 4 : 'IV', 5 : 'V', 9 : 'IX', 10 : 'X', 40 : 'XL', 50 : 'L', 90 : 'XC', 100 : 'C', 400 : 'CD', 500 : 'D', 900 : 'CM', 1000 : 'M' }
number = random.randrange(4000)
string = ''

for roman in sorted(numerals, reverse=True):
    if (number / roman):
        multiplier = number / roman
        string += numerals[roman]*multiplier
        number = number - (multiplier*roman)

print string

Published Solution

The above solutions were what I used to test and run before submitting, when you actually submit it has to be as a CheckIO function. The real code submitted can be found below here.