Using the 'randint' function from the 'random' module (https://docs.python.org/3/library/random.html#random.randint),
develop a function that emulates the roll of a dice with $n$ sides.
For $n=6$, devise and implement a test to check that it is a fair dice.
In [2]:
from random import randint
def roll(n):
"Roll of an n-sided dice"
return randint(1, n)
In [3]:
def test_six_sided_dice(n_rolls):
"Emulates n rolls of a 6-sided dice and checks the frequency of each side"
# Initialize a list to store the result of the roll
rolls = [0, 0, 0, 0, 0, 0]
# Roll the dice and store the result
for i in range(n_rolls):
rolls[roll(6)-1] += 1
# Calculate the frequency of each side
for i in range(6):
rolls[i] = rolls[i] / n_rolls
return rolls
# Emulate 100000 rolls
test_six_sided_dice(100000)
Out[3]:
In [4]:
# Import the compression module
import zlib
# Create a string that we wish to compress
text = """
Welcome, dear Rosencrantz and Guildenstern!
Moreover that we much did long to see you,
The need we have to use you did provoke
Our hasty sending. Something have you heard
Of Hamlet's transformation; so call it,
Sith nor the exterior nor the inward man
Resembles that it was. What it should be,
More than his father's death, that thus hath put him
So much from the understanding of himself,
I cannot dream of: I entreat you both,
That, being of so young days brought up with him,
And sith so neighbour'd to his youth and havior,
That you vouchsafe your rest here in our court
Some little time: so by your companies
To draw him on to pleasures, and to gather,
So much as from occasion you may glean,
Whether aught, to us unknown, afflicts him thus,
That, open'd, lies within our remedy."""
# Convert Python string to bytes, and check type
text_bytes = text.encode("utf-8")
print(type(text_bytes))
# Get number of bytes (memory) used to store string
print("Number of bytes for uncompressed string:", len(text_bytes))
# Compress string and get number of byes used for compressed string
text_comp = zlib.compress(text_bytes)
print("Number of bytes for compressed string:", len(text_comp))
# Display the compression efficiency
print("Compression efficiency: ", len(text_comp)/len(text_bytes))
# Decompress the string
text_decomp = zlib.decompress(text_comp)
# Check that original and decompressed strings are the same
if text == text_decomp.decode("utf-8"):
print("All good: original and decompressed strings are the same.")
else:
print("Problem: original and decompressed strings differ.")
Using the above as a guide, examine the compression efficiency of
To help you, the below function generates a random string of length N:
In [5]:
import random
import string
def random_string(N):
return ''.join([random.choice(string.ascii_letters + string.digits) for n in range(N)])
print(random_string(8))
In [6]:
def compression_efficiency(string):
"Calculate the compression efficiency obtained applying zlib.compress"
# Convert Python string to bytes
text_bytes = string.encode('utf-8')
# Compress string
text_comp = zlib.compress(text_bytes)
# Calculate the compression efficiency
return len(text_comp)/len(text_bytes)
# Comparison of compression efficiency (the smaller the better)
print('Compression efficiency for Shakespeare\'s passage repeated 100 times:', compression_efficiency(text*100))
print('Compression efficiency for a random string of the same length:', compression_efficiency(random_string(len(text)*100)))