def add(a, b):
    s = a + b
    return s
 
a = 10
b = 20
s = add(a, b)
print (s)

T1 (1p) Having a list of numbers, write a function to calculate the sum of all elements in the list. Tip: List given as input, using a for loop

import math
list1 = [1, 3, 4, 5, 8]
list3 = [1, 3, -4, 5, -8, -12]
weights1 = [0.2, 0.3, 0.6, 0.1, 0.5]
list2 = [1, 3, 4, 5, 7, 8]
 
# function to compute the arithmetic mean of a list
 
def my_mean(v):
    s_elem = sum(v)
    n_elem = len(v)
    return s_elem / n_elem
 
# function to compute the weighted arithmetic mean of a list
 
def my_pmean(v, p):
    s_pond = sum(p)
    i = 0
    s_lp = 0
    while i < len(v):
        s_lp += v[i] * p[i]
        i += 1
    return s_lp / s_pond
 
# function to compute the variance and standard deviation of a list
 
def my_stdvar(v):
    s = 0
    m = my_mean(v)
    n = len(v)
    for elem in v:
        s += (elem - m)**2
    return s / n, math.sqrt(s / n)
 
# function to compute the L2-norm normalization for list
 
def l2norm(v):
    new_list = []
    s = 0
    # compute the L2 norm
    for elem in v:
        s += elem**2
    s = math.sqrt(s)
 
    # list normalization using the L2 norm
    for elem in v:
        new_elem = elem / s
        new_list.append(new_elem)
 
    # TODO: same task with list comprehension    
 
    return new_list
 

T2.1 (1p) Use the functions to compute the arithmetic mean, weighted arithmetic mean, variance, standard deviation and L2-norm normalization of the list

T2.2 (2p) Implement the functions using list comprehension, without using for loops

module1.py

def hello_name(name):
    print("Hello " + name)

main.py

# import a single resource from a module
from module1 import hello_name
hello_name("Alex")
 
# import all resources from a module
from module1 import *
hello_name("Alex")
 
# import the module
import module1
module1.hello_name("Alex")
 
# import the module using an alias
import module1 as m
m.hello_name("Alex")

T3 (2p) Create two Python files (.py) in the same project folder, as shown in the example. Run the program main.py and check the output in the console

my_list = [1, 2, 3, 4, 5]
print(my_list)
 
# add an element to the list
my_list.append(6)
print(my_list)
 
# combine lists
my_other_list = [7, 8, 9, 10]
my_list.extend(my_other_list)
print(my_list)
 
# sort list (descending)
my_list.sort(reverse=True)
print(my_list)
 
# check if an element is found in the list
# (python specific, normally used with sets or dictionaries)
print(1 in my_list)
print(10 in my_list)

# declare a set
s = {"apple", "banana", "cherry"}
print(s)
 
# access items
for x in s:
    print(x)
 
# check if "banana" is present in the set
print("banana" in s)

Modify

# declare an empty set
s=set()
s=set([])
 
# add items
s.add("apple")
 
# add more items
s.update(["orange", "mango", "grapes"])
print(s)
 
s.add("orange") # does nothing, the element is already in the set
print(s)
# get the length of a set
print(len(s))
 
# remove item
s.remove("orange")
print(s)

Operations (set theory)

# declare a set using a list:
s1 = set(['a', 'b', 'd'])
s2 = set(['a', 'b', 'c', 'e'])
s3 = set(['a', 'd'])
print("s1:", s1)
print("s2:", s2)
print("s3:", s3)
 
# verify if a set is a subset of another set:
print("s1 subset of s3:")
print(s1.issubset(s3))
 
print("s3 subset of s1:")
print(s3.issubset(s1))
 
# get the union between 2 sets:
print("union s1, s3:")
print(s1.union(s3))
 
# get the intersection between 2 sets:
print("intersection s1, s2:")
print(s1.intersection(s2))
 
# get the difference between 2 sets:
print("s1-s2:")
print(s1.difference(s2))
 
print("s2-s1:")
print(s2.difference(s1))

T4 (4p) The set is a collection of unordered (and unique) elements. Use this to your advantage to remove duplicates from a list

Hint:

• you can create a set from a list: s = set([1,2,3])
• you can create a list from a set: v = list({1, 2, 3})

d = {}
d = dict()
 
# a dictionary with keys and values can be declared as follows:
d = {'a': 1, 'b': 2, 'c': 3, 'd': 4}
 
# adding a new key to a dictionary:
d = {}
d['a'] = 1
d['b'] = 2
d['c'] = 3
d['d'] = 4
 
# looping through a dictionary:
for key in d:
   print(key)  # print only key
   print(key, d[key])  # print key and value d[key]
 
 
# looping using the key and value:
for key, value in d.items():
    print(key, value)
 
# to verify if a dictionary has a specific key use the get() function:
if d.get('a'):  # verify if the dictionary contains the key 'a'
    print('ok')
else:
    print('not found')
 
# alternative
if 'a' in d:
    print('ok')
else:
    print('not found')

# counting the number of times a letter appears in a string:
s = 'ana are mere'
d = {}
for elem in s:  # pass through all the characters in the string
    if d.get(elem):  # verify if the character exists in the dictionary
        d[elem] += 1  # if it exist add 1 to the value for that character
    else:  # if it doesn’t exist initialize a new key with the value of the character
        d[elem] = 1  # and initialize the value (which is the counter) to 1

T5 (4p - bonus) You have a list of numbers. Write a program to show the frequency of each number as the number of times that number is found in the list.

Hint:

• Use dictionaries to keep track of each element