import random  # random is a library

from pause import enter_when_ready

# see http://www.cs.virginia.edu/~cs1112/documents/modules/random/ for a
# discussion of interval notation

# important one below is [ x, y  ) -- this means all values starting with x
# and up to but not including y


# if we do not set the seed, the random number sequence differs with every run

x = random.random() # random returns a float number from 
                    # float interval [0, 1)

                    # because we did not set the seed, every time we run
                    # the program the values assigned to x is different

# running random.seed(x)...the seed is influenced by x

print(  "x = ", x  )

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 ) # seed is a way of helping us "control" or "influence" the randomness
# random.seed('Simone') # the first value generated from this seed is 0.9538100080756253
# the randomness is based on the fact that computers represent numbers as binary values (0s and 1s) and a bunch of stuff about time

y = random.random() # first number from seed( 1112 ) is always
                    # 0.28143470043335006. how do we know this, we ran the
                    # program and recorded the value

print( "y = ", y )

z = random.random()     # see what z is when you run this program with certain seeds...z's value isn't the same as y,
                            # but z doesn't change value
print( "z = ", z )

# random.seed( 1112 )
#
# a = random.random()     # see what a is when you run this program...it should be the same as x
# print( "a = ", a )

# b = random.seed(1112)
# print(b)              # what happens when we run this?

enter_when_ready()


# rand.uniform( x, y ) returns a random float from the interval [ x. y )

n1_uniform = random.uniform( 1.5, 7.25 )

random.seed()       # pick a new sequence of numbers based on the current time

n2_uniform = random.uniform( 1.5, 7.25 )

print( "uniform values: ", n1_uniform, "and", n2_uniform )

enter_when_ready()

# note: random.random() and random.uniform( 0, 1 ) are synonyms

# rand.gauss( m, s ) returns a random normally distributed float 
# the generated value have mean m and standard deviation s

n1_gauss = random.gauss( 1.5, 1.25 ) # mean = 1.5, std dev = 1.25
n2_gauss = random.gauss( 1.5, 1.25 )

print( "gaussian values:", n1_gauss, "and", n2_gauss )

enter_when_ready()

bottom = 2
top    = 7
step   = 2

# 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 )   # we will get the value 0, 1, 2, 3, 4, 5, or 6

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

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

enter_when_ready()

x = random.randrange( bottom, top )  # we will get the value 2, 3, 4, 5, or 6
print( "randrange( ", bottom, ",", top," ) gave", x )

enter_when_ready()

# 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 ) # we will get the value 2, 4, or 6

enter_when_ready()


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

alphabet = "qwertyuiopasdfghjklzxcvbnm"  # a string is a collection...a list of characters
letter = random.choice( alphabet )   # give random.choice() a collection, and it will hand you some random value from the collection

print( "We like letter", letter )

print()

# 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' ]  # a list is a list

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 )  # if you give me a list, I'm going to reorder the elements
print( "The ordering of days is now", days )

print()

# feel free to play around with these random functions on your own time and learn more about these functions!