''' Purpose: introduce some functions from module random
'''

import random # want random values, then we need the random module

import pause 

print( 'Because we have not the seed before generating values for x and ' )
print( 'y, we can expect the first two values to be randon every run' )

x = random.random() # random() returns a float number from float interval [0, 1 )
y = random.random() # because we did not set the seed, every time we run the program
                    # should assign different values assigned to 

print( 'x =', x  )
print( 'y =', y  )

pause.enter_when_ready()

# if we pass a seed value, the random number generator is configured to
# produce the same sequence of random values from that point on.

random.seed( 1112 ) # first number from seed( 1112 ) is always
x = random.random() # 0.28143470043335006. how do we know this, we ran the

random.seed( 1112 ) # program and recorded the value
y = random.random()

print( 'Because we set the seed to the same value before generating values for x' )
print( 'y, they are going to have the same value' )

print( 'x =', x )
print( 'y =', y )

pause.enter_when_ready()

# let's make the seed randon
random.seed()

bottom = 2
top    = 7
step   = 2

# function random.randrange( x )
#     returns a random integer value from the interval [ 0, x ); values are
#     equally likely to occur. we say that the generated numbers are from base x

x = random.randrange( top )

print( 'randrange(', top, ') gave', x )

pause.enter_when_ready()

# function random.randrange( x, y )
#     returns a random integer value from the interval [ x, y ); values are
#     equally likely to occur

x = random.randrange( bottom, top )
print( 'randrange(', bottom, ',', top, ') gave', x )

pause.enter_when_ready()

# function random.randrange( x, y, s ) returns a random integer value from the interval
#     [ x, y ); values are equally likely to occur; generated numbers are of form
#     x + ( i * s )

x = random.randrange( bottom, top, step )

print( 'randrange(', bottom, ',', top, ',', step, ') gave', x )

pause.enter_when_ready()

# function random.choice( s ) if s is a string, the method returns a random
#     character from the string; the characters are equally likely to occur

alphabet = 'qwertyuiopasdfghjklzxcvbnm'

letter = random.choice( alphabet )

print( 'We like letter', letter )

print()

# function random.choice( s ) if s is a sequence, the method returns a random
#       element from the sequence

days = [ 'Su', 'Mo', 'Tu', 'We', 'Th', 'Fr', 'Sa' ]

appointment = random.choice( days )

print( 'We will next see you on', appointment )

print()

# random.shuffle( s ) if s is a sequence, randomizes the ordering of
                            # the values in the sequence

random.shuffle( days )
print( 'The ordering of days is now', days )

print()