Some Python Basics

some-python-basics.py

print "hello world"

""" This is a multi-line comment... no it's not
int main() {
  return 0;
}
"""

def main():
  return 0

# Weakly typed
a = 42
a = "hello"

day = 'tuesday'

if day == 'friday':
  print "I'm in love!"
elif day == 'tuesday':
  print "not as fun"

i = 0
while i < 50:
  #print "hi"
  i += 1

names = ['John', 'Abbey', 'James', 'Danny']

"""
for (int i = 0; i < ITEMS_SIZE; i += 1) {
  type name = names[i];
}
"""
for name in names:
  print "hello " + name

print names

print names[2]

try:
  names[90]
except Exception as e:
  print e

my_hash_table = {}

my_hash_table['name'] = 'John'

my_hash_table['favorite_drink'] = 'scotch'

my_hash_table[42] = 'the answer'

print my_hash_table
print my_hash_table['favorite_drink']

pair = ('John', 'scotch')
triple = ('John', 'scotch', 20)

print pair[0]

my_hash_table[pair] = 'hi there'

print my_hash_table

print my_hash_table[pair]

print 12 + 99
print 'a' + 'b'

numbers = [1, 2, 3] + [4, 5, 6]

# LOOK AT NUMPY http://www.numpy.org/
print numbers[3:]

print numbers[-1]
print numbers[-2]
print numbers[1:-1]
print numbers[::-1]

# List comprehensions!!!!
# [<what's being returned> <how you're looping> <?conditional?>]
evens_tripled = [i*3 for i in numbers if i % 2 == 0]

print evens_tripled

# checking containment
print 42 in evens_tripled
print 18 in evens_tripled

# Strings are OBJECTS
# OBJECTS have methods
# Methods are functions that are attached to objects
print ', '.join(names)

# In Python sometimes
# - It's hard to guess what's gonna be a function vs. a method
# - If it's a method, it's hard to guess what it's on

names_containing_J = [name for name in names if 'J' in name]

# `and` and `or` not && and ||

print names_containing_J

# TODO: Visit polymorphism

class Person:
  # Constructor
  def __init__(self, name):
    self.name = name

  def greet(self):
    print "Hello " + self.name

john = Person('John')

john.greet()

print john.name

# Polymorphism through "duck-typing"

class Dog:
  def greet(self):
    print "Woof"

fido = Dog()

for greetable in [john, fido]:
  greetable.greet()

with open('./hello.py', 'r') as f:
  text = f.read()

print text