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

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

print( 'By default, we can expect the random number generator to produce' )
print( 'a difference sequence of values every time we start it up' )

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 set the 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 0.28143470043335006.
x = random.random()     # 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 random
random.seed()
bottom = 2
top    = 7
step   = 2

# function random.randrange( x ) returns a random integer from interval [ 0, x );
#     that is, it generates a base x number

x = random.randrange( top )

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

pause.enter_when_ready()

# function random.randrange( x, y ) returns a random integer from interval [ x, y )

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

pause.enter_when_ready()

# function random.randrange( x, y, s ) returns random integer value from interval
#     [ x, y ); numbers are of form x + ( i * s )

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

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

pause.enter_when_ready()

# function random.choice( s ) if s is a string, returns a random character from s

keyboard = 'qwertyuiopasdfghjklzxcvbnm'

letter = random.choice( keyboard )

print( 'choice( \'' +  keyboard + '\' ):', letter )

pause.enter_when_ready()

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

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

day = random.choice( days )

print( 'choice(', days, '):', day )

pause.enter_when_ready()

# random.shuffle( s ) if s is a sequence, randomly reorders s

random.shuffle( days )
print( 'Days is now:', days )

print()