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

import random # want random values, then we need the random module
              # helps us generate random numbers or choose a random element from a sequence

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 to x and y

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 )

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

# seed helps us control randomness; it provides a basis off of which future randomness is based

# you do not need to set random.seed() equal to some variable to make it work

# seed helps us influence whatever randomness is generated; if you want control, seed is the way to do it
# it helps keep output consistent so that you can better see what could be going on in your program
# it's also a great way of standardizing programs

# See what happens when you run these lines!
# Also a seed can be pretty much anything so long as it's legal Python.
# random.seed('wubba lubba dub dub')
# z = random.random()  # generates a decimal between 0 and 1
# u = random.random()
# print(z, u)
#
# random.seed('wubba lubba dub dub!')
# d = random.random()

pause.enter_when_ready()

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

#if you give nothing to seed it uses the time
# so you don't see the same numbers over an over unlike a set seed

bottom = 2
top    = 7
step   = 3

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

# 0 to 6 is base 7
# 0 to 9 is base 10
# 0 to 1 is base 2

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 )  # from 2 to 6
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' ] # when things are in brackets [], the data type is a list
# lists can contain so many things not just strings.
# [ 2, '3', 2.789] this is a heterogeneous list. They are allowed in python.
# most lists are homogeneous

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()

pause.enter_when_ready()

print( 'randrange(', bottom, ',', top, ') gave', x )
# bottom and top have to be ints

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 )
#     ranging from x to y-1 in intervals of s

x = random.randrange( bottom, top, step ) # from 2 to 6 in intervals of 2 is 2, 4, 6

# the order of the values in the parentheses makes a difference...
# **try different numbers on your own and see what happens!**

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


# generates a number from 0 to 100 that is a multiple of 5
mult_of_5_from_0_to_100 = random.randrange(0, 101, 5)  # random.randrange(starting_number, ending_number, interval)
print('randrange(', '0', ',', '101', ',', '5', ') gave', mult_of_5_from_0_to_100)

# how do I get a random number from x to y using randrange?
# start your range from x and end it at y+1