Hi, my name is Steve Howell, and I have been programming in Python more or less full time since 2001.
In 2010 I attempted to submit a patch to CPython shown here: ProposalToSpeedUpListOperations
I mainly use Python at work now, but I have also contributed to open source projects. Here are some things that I've done in the Open Source world:
http://gvr.sourceforge.net/ (Guido van Robot learning IDE)
the initial version of LocalSiteMap feature in MoinMoin
Here is an early version of the code on the SimplePrograms page. I wrote most of the initial code, with helpful edits from other folks.
I am keeping it here for posterity. The code below is free for use under the Python license. I encourage you to try building up your own suite of examples.
One thing unique about the format below is that each program gets one line longer than the previous.
All of this code has been tested on 2.4 or 2.5.
------ 1 Output
print 'hello world'
------ 2 Looping
for name in ['peter', 'paul', 'mary']:
print name
------ 3 Input, comments
# This is a Python comment. \n is a newline
name = raw_input('What is your name?\n')
print 'Hi', name
------ 4 Fibonacci, tuple assignment
parent_rabbits, baby_rabbits = (1, 1)
while baby_rabbits < 100:
print 'This generation has %d rabbits' % baby_rabbits
parent_rabbits, baby_rabbits = (baby_rabbits, parent_rabbits + baby_rabbits)
------ 5 Functions
def greet(name):
print 'hello', name
greet('Jack')
greet('Jill')
greet('Bob')
------ 6 Import, regular expresssions
import re
for test_string in [ '555-1212', 'ILL-EGAL']:
if re.match('\d\d\d-\d\d\d\d$', test_string):
print test_string, 'is a valid US local phone number'
else:
print test_string, 'rejected'
------ 7 Dictionaries, generator expressions
prices = {'apple': 0.40, 'banana': 0.50}
my_purchase = {
'apple': 1,
'banana': 6}
grocery_bill = sum(prices[fruit] * my_purchase[fruit]
for fruit in my_purchase)
print 'I owe the grocer $%.2f' % grocery_bill
------ 8 Command line arguments, exception handling
#!/usr/local/bin/python
# This program adds up integers in the command line
import sys
try:
total = sum(int(arg) for arg in sys.argv[1:])
print 'sum =', total
except ValueError:
print 'Please supply integer arguments'
------ 9 Opening files
# indent your Python code to put into an email
import glob
# glob supports Unix style pathname extensions
python_files = glob.glob('*.py')
for fn in sorted(python_files):
print ' ------'
for line in open(fn):
print ' ' + line.rstrip()
print
------ 10 Time, conditionals
import time
now = time.localtime()
hour = now.tm_hour
if hour < 8: print 'sleeping'
elif hour < 9: print 'commuting'
elif hour < 17: print 'working'
elif hour < 18: print 'commuting'
elif hour < 20: print 'eating'
elif hour < 22: print 'resting'
else: print 'sleeping'
------ 11 Triple-quoted strings, while loop
REFRAIN = '''
%d bottles of beer on the wall,
%d bottles of beer,
take one down, pass it around,
%d bottles of beer on the wall!
'''
bottles_of_beer = 99
while bottles_of_beer > 1:
print REFRAIN % (bottles_of_beer, bottles_of_beer,
bottles_of_beer - 1)
bottles_of_beer -= 1
------ 12 List slicing
def sieve_of_eratosthenes(candidates):
i = 0
while True:
divisor = candidates[i]
if divisor * divisor > candidates[-1]:
return candidates
else:
i += 1
candidates = candidates[:i] + \
[num for num in candidates[i:]
if num % divisor != 0]
print sieve_of_eratosthenes(range(2,100))
------ 13 Unit testing
# Let's write reusable code, and unit test it.
def add_money(amounts):
# do arithmetic in pennies so as not to accumulate float errors
pennies = sum([round(int(amount * 100)) for amount in amounts])
return float(pennies / 100.0)
if __name__ == '__main__':
import unittest
class TestAddMoney(unittest.TestCase):
def test_float_errors(self):
self.failUnlessEqual(add_money([0.13, 0.02]), 0.15)
self.failUnlessEqual(add_money([100.01, 99.99]), 200)
self.failUnlessEqual(add_money([0, -13.00, 13.00]), 0)
unittest.main()
------ 14 Classes
class BankAccount:
def __init__(self, initial_balance = 0):
self.balance = initial_balance
def deposit(self, amount):
self.balance += amount
def withdraw(self, amount):
self.balance -= amount
def overdrawn(self):
return self.balance < 0
my_account = BankAccount()
my_account.deposit(15)
my_account.withdraw(5)
print my_account.balance
print my_account.overdrawn()
------ 15 itertools
import itertools
lines = '''
This is the
first paragraph.
This is the second.
'''.splitlines()
# Use itertools.groupby and bool to return groups of
# consecutive lines that either have content or don't.
for has_chars, frags in itertools.groupby(lines, bool):
if has_chars:
print ' '.join(frags)
# PRINTS:
# This is the first paragraph.
# This is the second.