# Converting real to integer
print 'int(3.14) =', int(3.14)

# Converting integer to real
print 'float(5) =', float(5)

# Calculation between integer and real results in real
print '5.0 / 2 + 3 = ', 5.0 / 2 + 3

# Integers in other base
print "int('20', 8) =", int('20', 8) # base 8
print "int('20', 16) =", int('20', 16) # base 16

# Operations with complex numbers
c = 3 + 4j
print 'c =', c
print 'Real Part:', c.real
print 'Imaginary Part:', c.imag
print 'Conjugate:', c.conjugate()

s = 'Camel'

# Concatenation
print 'The ' + s + ' ran away!'

# Interpolation
print 'Size of %s => %d' % (s, len(s))

# String processed as a sequence
for ch in s: print ch

# Strings are objects
if s.startswith('C'): print s.upper()

# what will happen? 
print 3 * s
# 3 * s is consistent with s + s + s

# Zeros left
print 'Now is %02d:%02d.' % (16, 30)

# Real (The number after the decimal point specifies how many decimal digits )
print 'Percent: %.1f%%, Exponencial:%.2e' % (5.333, 0.00314)

# Octal and hexadecimal
print 'Decimal: %d, Octal: %o, Hexadecimal: %x' % (10, 10, 10)

musicians = [('Page', 'guitarist', 'Led Zeppelin'),
('Fripp', 'guitarist', 'King Crimson')]

# Parameters are identified by order
msg = '{0} is {1} of {2}'

for name, function, band in musicians:
    print(msg.format(name, function, band))

# Parameters are identified by name
msg = '{greeting}, it is {hour:02d}:{minute:02d}'

print msg.format(greeting='Good Morning', hour=7, minute=30)

# Builtin function format()
print 'Pi =', format(3.14159, '.3e')

print 'Python'[::-1]
# shows: nohtyP

import string

# the alphabet
a = string.ascii_letters

# Shifting left the alphabet
b = a[1:] + a[0]

# The function maketrans() creates a translation table
# from the characters of both strings it received as parameters.
# The characters not present in the table will be 
# copied to the output.
tab = string.maketrans(a, b)

# The message...
msg = '''This text will be translated..
It will become very strange.
'''
# The function translate() uses the translation table
# created by maketrans() to translate the string
print string.translate(msg, tab)

import string

# Creates a template string
st = string.Template('$warning occurred in $when')

# Fills the model with a dictionary
s = st.substitute({'warning': 'Lack of electricity',
    'when': 'April 3, 2002'})

# Shows:
# Lack of electricity occurred in April 3, 2002
print s

import UserString

s = UserString.MutableString('Python')
s[0] = 'p'

print s # shows "python"

# Unicode String 
u = u'Hüsker Dü'
# Convert to str
s = u.encode('latin1')
print s, '=>', type(s)

# String str
s = 'Hüsker Dü'
u = s.decode('latin1')

print repr(u), '=>', type(u)

# a new list: 70s Brit Progs
progs = ['Yes', 'Genesis', 'Pink Floyd', 'ELP']

# processing the entire list
for prog in progs:
    print prog

# Changing the last element
progs[-1] = 'King Crimson'

# Including
progs.append('Camel')

# Removing
progs.remove('Pink Floyd')

# Ordering 
progs.sort()

# Inverting
progs.reverse()

# prints with number order
for i, prog in enumerate(progs):
    print i + 1, '=>', prog

# prints from de second item
print progs[1:]

my_list = ['A', 'B', 'C']
print 'list:', my_list

# The empty list is evaluated as false
while my_list:
    # In queues, the first item is the first to go out
    # pop(0) removes and returns the first item 
    print 'Left', my_list.pop(0), ', remain', len(my_list)

# More items on the list
my_list += ['D', 'E', 'F']
print 'list:', my_list

while my_list:
    # On stacks, the first item is the last to go out
    # pop() removes and retorns the last item
    print 'Left', my_list.pop(), ', remain', len(my_list)

# Data sets
s1 = set(range(3))
s2 = set(range(10, 7, -1))
s3 = set(range(2, 10, 2))

# Shows the data
print 's1:', s1, '\ns2:', s2, '\ns3:', s3

# Union
s1s2 = s1.union(s2)
print 'Union of s1 and s2:', s1s2

# Difference
print 'Difference with s3:', s1s2.difference(s3)

# Intersectiono
print 'Intersection with s3:', s1s2.intersection(s3)

# Tests if a set includes the other
if s1.issuperset([1, 2]):
    print 's1 includes 1 and 2'

# Tests if there is no common elements
if s1.isdisjoint(s2):
    print 's1 and s2 have no common elements'

# Progs and their albums
progs = {'Yes': ['Close To The Edge', 'Fragile'],
    'Genesis': ['Foxtrot', 'The Nursery Crime'],
    'ELP': ['Brain Salad Surgery']}

# More progs
progs['King Crimson'] = ['Red', 'Discipline']

# items() returns a list of 
# tuples with key and value 
for prog, albums in progs.items():
    print prog, '=>', albums

# If there is 'ELP', removes
if progs.has_key('ELP'):
    del progs['ELP']

# Sparse Matrix implemented
# with dictionary

# Sparse Matrix is a structure
# that only stores values that are
# present in the matrix

dim = 6, 12
mat = {}

# Tuples are immutable
# Each tuple represents
# a position in the matrix
mat[3, 7] = 3
mat[4, 6] = 5
mat[6, 3] = 7
mat[5, 4] = 6
mat[2, 9] = 4
mat[1, 0] = 9

for lin in range(dim[0]):
    for col in range(dim[1]):
        # Method get(key, value)
        # returns the key value
        # in dictionary or 
        # if the key doesn't exists
        # returns the second argument
        print mat.get((lin, col), 0),
    print

# Matrix in form of string
matrix = '''0 0 0 0 0 0 0 0 0 0 0 0
9 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 4 0 0
0 0 0 0 0 0 0 3 0 0 0 0
0 0 0 0 0 0 5 0 0 0 0 0
0 0 0 0 6 0 0 0 0 0 0 0'''

mat = {}

# split the matrix in lines
for row, line in enumerate(matrix.splitlines()):

    # Splits the line int cols
    for col, column in enumerate(line.split()):

        column = int(column)
        # Places the column in the result,
        # if it is differente from zero
        if column:
            mat[row, col] = column

print mat
# The counting starts with zero
print 'Complete matrix size:', (row + 1) * (col + 1)
print 'Sparse matrix size:', len(mat)

print 0 and 3 # Shows 0
print 2 and 3 # Shows 3

print 0 or 3 # Shows 3
print 2 or 3 # Shows 2

print not 0 # Shows True
print not 2 # Shows False
print 2 in (2, 3) # Shows True
print 2 is 3 # Shows False