Taste of Python Power

Python is a programming language that lets you work more quickly and integrate your systems more effectively. You can learn to use Python and see almost immediate gains in productivity and lower maintenance costs. Python runs on Windows, Linux/Unix, Mac OS X, and has been ported to the Java and .NET virtual machines. Python is free to use, even for commercial products, because of its OSI-approved open source license. The below is a quick taste of the power of Python language:

List Comprehensions	print [x+1 for x in xrange(10) if x%3 == 0] [1, 4, 7, 10]
Dictionary Defaults	my_dict = {} world = my_dict.get('hello', 'world') print world world
Filter	from math import sqrt def prime(n):     if n < 1 : return False     for d in range(2, int(sqrt(n))+1):         if n % d == 0: return False     return True print [n for n in range(20) if prime(n)] print filter(prime, range(20)) [1,2,3,5,7,11,13,17,19] [1,2,3,5,7,11,13,17,19]
Unzip	tups = [(1,4,7),(2,5,8),(3,6,9)] t0s, t1s, t2s = zip(*tups) print t0s print t1s print t2s (1,2,3) (4,5,6) (7,8,9)
dict() and zip() make for a powerful combination	voters = ['friends','neighbors','countrymen'] counts = [10,5,800] print dict(zip(voters,counts)) votes = ['yes',66,'no',77,'abstain',9] print dict(zip(votes[:-1:2],votes[1::2])) {‘neighbours’:5, ‘countrymen’:800, ‘friends’:10} {‘yes’:66, ’abstain’:9, ’no’:77}
Triple quotes	print """Dear John, How are you? Best of luck, George.""" Dear John, How are you? Best of luck, George.
Map	print map(int, "10 20 30".split()) [10,20,30]
Multiple Return Values	def get_center():     return (10, 10) x, y = get_center() print "The center is at X: %d, Y: %d" % (x, y) The center is at X: 10, Y: 10
Expanding Arrays to Function Arguments	def add(n1, n2):     return n1 + n2 numbers = [3, 4] print add(*numbers) 7
Collections	import collections d=collections.defaultdict(int) d["never seen before"] += 1 print d["never seen before"] 1
Generator Functions	def lottery_numbers():     my_numbers = [1,3,2,5,4,6]     for n in my_numbers:         if n > 3:             yield n+10         else:             yield n for n in lottery_numbers():     print n 1 3 2 15 14 16
Zip	names = ['john', 'peter', 'robert'] ages = [24, 26, 35] cars = ['BMW', 'Audi', 'Ford'] print zip(names, ages, cars) [('john', 24, 'BMW'), ('peter', 26, 'Audi'), ('robert', 35, 'Ford')]
Ordered and Named Function Arguments	def f(*args, **kwargs):     print(args)     print(kwargs) f(1,2,3,named1="keyword arg1", another="another kwarg") (1, 2, 3) {'named1': 'keyword arg1', 'another': 'another kwarg'}
Locals and Strings	world = "earth" print "hello %(world)s" % locals() hello earth
Glass Half Empty?	from __future__ import division import sys print 1/2 + 1/2 print sys.version 1.0 2.7.2 (default, Jun 24 2011, 12:21:10) [MSC v.1500 32 bit (Intel)]
Set Comprehensions	print {1, 2, 2, 3, 1} names = ["Foo", "bar", "foo", "Baz", "CATS", "dogs"] print {name.upper() for name in names if name[0] in 'fFbB'} set([1, 2, 3]) set(['BAZ', 'FOO', 'BAR'])
Functions as Objects	def talk(text):     print text def think(idea):     print "thinking about %s" % idea def do_something(what, with_what):     what(with_what) do_something(talk, 'hello!') do_something(think, 'food...') hello! thinking about food...
Funception	def outside(a, b):     def inside(x):         return x + 5     return inside(a) * inside(b) print outside(1, 2) 42
Addition made easy	print eval('+'.join(map(str, [1, 1]))) 2