Basic python notebook

Let's explore more in depth the basics¶

Variables¶

In [12]:

# Assigning a value to a variable:
x = 5
y = 10
z = x + y
print(z) # Output: 15

# Assigning a value to a variable: x = 5 y = 10 z = x + y print(z) # Output: 15

15

In [11]:

# Assigning a value to multiple variables at once:
a, b, c = 1, 2, 3
print(a) # Output: 1
print(b) # Output: 2
print(c) # Output: 3

# Assigning a value to multiple variables at once: a, b, c = 1, 2, 3 print(a) # Output: 1 print(b) # Output: 2 print(c) # Output: 3

1
2
3

In [10]:

# Assigning a value to a variable and then reassigning a new value:
name = "John"
print(name) # Output: John
name = "Eric"
print(name) # Output: Eric

# Assigning a value to a variable and then reassigning a new value: name = "John" print(name) # Output: John name = "Eric" print(name) # Output: Eric

John
Eric

In [9]:

# Assigning a value to a variable and then using it in a calculation:
num1 = 15
num2 = 20
result = num1 * num2
print(result) # Output: 300

# Assigning a value to a variable and then using it in a calculation: num1 = 15 num2 = 20 result = num1 * num2 print(result) # Output: 300

300

In [8]:

# Using a variable as an input for a function:
name = "Michael"
age = 25
print("My name is " + name + " and I am " + str(age) + " years old.")

# Using a variable as an input for a function: name = "Michael" age = 25 print("My name is " + name + " and I am " + str(age) + " years old.")

My name is Michael and I am 25 years old.

In [7]:

# Assigning a value to a variable and then using it in a loop:
word = "hello"
for letter in word:
    print(letter)

# Assigning a value to a variable and then using it in a loop: word = "hello" for letter in word: print(letter)

h
e
l
l
o

In [6]:

# Assign a value to a variable and then using it in a data structure, such as a list:
x = 6
numbers = [1, 2, 3, 4, 5]
numbers.append(x)
print(numbers)

# Assign a value to a variable and then using it in a data structure, such as a list: x = 6 numbers = [1, 2, 3, 4, 5] numbers.append(x) print(numbers)

[1, 2, 3, 4, 5, 6]

Data types¶

In [16]:

# lists 

# Creating a list
a = [1, 2, 3, 4, 5]

# Accessing elements in a list
print(a[2])

# Modifying elements in a list
a[2] = 6
print(a)

# Adding elements to a list
a.append(7)
print(a) 

# Removing elements from a list
a.remove(6)
print(a)

# lists # Creating a list a = [1, 2, 3, 4, 5] # Accessing elements in a list print(a[2]) # Modifying elements in a list a[2] = 6 print(a) # Adding elements to a list a.append(7) print(a) # Removing elements from a list a.remove(6) print(a)

3
[1, 2, 6, 4, 5]
[1, 2, 6, 4, 5, 7]
[1, 2, 4, 5, 7]

In [19]:

# tuples

# Creating a tuple
b = (1, 2, 3, 4, 5)

# Accessing elements in a tuple
print(b[2]) # Output: 3

# Tuples are immutable, so modifying elements is not possible

# Concatenating tuples
c = b + (6, 7)
print(c) # Output: (1, 2, 3, 4, 5, 6, 7)

# tuples # Creating a tuple b = (1, 2, 3, 4, 5) # Accessing elements in a tuple print(b[2]) # Output: 3 # Tuples are immutable, so modifying elements is not possible # Concatenating tuples c = b + (6, 7) print(c) # Output: (1, 2, 3, 4, 5, 6, 7)

3
(1, 2, 3, 4, 5, 6, 7)

In [18]:

# dict

# Creating a dictionary
d = {'a': 1, 'b': 2, 'c': 3}

# Accessing elements in a dictionary
print(d['b'])

# Modifying elements in a dictionary
d['b'] = 4
print(d) 

# Adding elements to a dictionary
d['d'] = 5
print(d)

# Removing elements from a dictionary
del d['a']
print(d)

# dict # Creating a dictionary d = {'a': 1, 'b': 2, 'c': 3} # Accessing elements in a dictionary print(d['b']) # Modifying elements in a dictionary d['b'] = 4 print(d) # Adding elements to a dictionary d['d'] = 5 print(d) # Removing elements from a dictionary del d['a'] print(d)

2
{'a': 1, 'b': 4, 'c': 3}
{'a': 1, 'b': 4, 'c': 3, 'd': 5}
{'b': 4, 'c': 3, 'd': 5}

In [22]:

# sets

# Creating a set
e = {1, 2, 3, 4, 5}

# Sets do not support indexing, so accessing elements is not possible

# Modifying elements in a set
e.add(6)
print(e)
e.remove(4)
print(e)

# Union and intersection of sets
f = {4, 5, 6, 7, 8}
print(e.union(f))
print(e.intersection(f))

# sets # Creating a set e = {1, 2, 3, 4, 5} # Sets do not support indexing, so accessing elements is not possible # Modifying elements in a set e.add(6) print(e) e.remove(4) print(e) # Union and intersection of sets f = {4, 5, 6, 7, 8} print(e.union(f)) print(e.intersection(f))

{1, 2, 3, 4, 5, 6}
{1, 2, 3, 5, 6}
{1, 2, 3, 4, 5, 6, 7, 8}
{5, 6}

In [20]:

# Creating a string
g = "Hello, World!"

# Accessing elements in a string
print(g[7])

# Modifying elements in a string is not possible as strings are immutable

# Concatenating strings
h = g + " How are you?"
print(h)

# Splitting a string
print(h.split())

# Creating a string g = "Hello, World!" # Accessing elements in a string print(g[7]) # Modifying elements in a string is not possible as strings are immutable # Concatenating strings h = g + " How are you?" print(h) # Splitting a string print(h.split())

W
Hello, World! How are you?
['Hello,', 'World!', 'How', 'are', 'you?']

Operators¶

In [23]:

a = [1, 2, 3]
b = [1, 2, 3]
c = a

print(a is b)
print(a is c)

a = [1, 2, 3] b = [1, 2, 3] c = a print(a is b) print(a is c)

False
True

In [24]:

numbers = [1, 2, 3, 4, 5]

print(3 in numbers)
print(6 in numbers)

numbers = [1, 2, 3, 4, 5] print(3 in numbers) print(6 in numbers)

True
False

In [25]:

numbers = [1, 2, 3, 4, 5]

print(3 not in numbers)
print(6 not in numbers)

numbers = [1, 2, 3, 4, 5] print(3 not in numbers) print(6 not in numbers)

False
True

In [26]:

list1 = [1, 2, 3]
list2 = [4, 5, 6]

list3 = list1 + list2
print(list3)

list1 = [1, 2, 3] list2 = [4, 5, 6] list3 = list1 + list2 print(list3)

[1, 2, 3, 4, 5, 6]

In [27]:

list1 = [1, 2, 3]

list2 = list1 * 3
print(list2)

list1 = [1, 2, 3] list2 = list1 * 3 print(list2)

[1, 2, 3, 1, 2, 3, 1, 2, 3]

In [28]:

print(2 ** 3)

print(2 ** 3)

8

In [33]:

print(7 // 3)
print(7 / 3)
print(7 % 3)

print(7 // 3) print(7 / 3) print(7 % 3)

2
2.3333333333333335
1

Control flow¶

if-elif-else statements - for loop - while loop¶

In [ ]:

# Example 1: Using "elif" to check multiple conditions
age = 25
if age < 18:
    print("You are a minor.")
elif age >= 18 and age < 30:
    print("You are a young adult.")
else:
    print("You are an adult.")

# Example 1: Using "elif" to check multiple conditions age = 25 if age < 18: print("You are a minor.") elif age >= 18 and age < 30: print("You are a young adult.") else: print("You are an adult.")

In [ ]:

# Example 2: Using "for" to iterate over a list
fruits = ["apple", "banana", "orange"]
for fruit in fruits:
    print(fruit)

# Example 2: Using "for" to iterate over a list fruits = ["apple", "banana", "orange"] for fruit in fruits: print(fruit)

In [ ]:

# Example 3: Using "while" to repeat a block of code
counter = 0
while counter < 5:
    print(counter)
    counter += 1

# Example 3: Using "while" to repeat a block of code counter = 0 while counter < 5: print(counter) counter += 1

In [ ]:

# Example 4: Using "break" and "continue" in a loop
numbers = [1, 2, 3, 4, 5]
for number in numbers:
    if number % 2 == 0:
        continue
    print(number)
    if number == 3:
        break

# Example 4: Using "break" and "continue" in a loop numbers = [1, 2, 3, 4, 5] for number in numbers: if number % 2 == 0: continue print(number) if number == 3: break

In [ ]:

# Example 5: Using "for" and "enumerate" to iterate over a list with index
fruits = ["apple", "banana", "orange"]
for i, fruit in enumerate(fruits):
    print(i, fruit)

# Example 5: Using "for" and "enumerate" to iterate over a list with index fruits = ["apple", "banana", "orange"] for i, fruit in enumerate(fruits): print(i, fruit)

Functions¶

In [34]:

# Example 1: A function that takes a list and returns the average of its elements
def average(numbers):
    return sum(numbers) / len(numbers)

result = average([1, 2, 3, 4, 5])
print(result)

# Example 1: A function that takes a list and returns the average of its elements def average(numbers): return sum(numbers) / len(numbers) result = average([1, 2, 3, 4, 5]) print(result)

3.0

In [ ]:

# Example 2: A function that uses a default value for an argument
def power(number, exponent=2):
    return number ** exponent

print(power(3))
print(power(3, 3))

# Example 2: A function that uses a default value for an argument def power(number, exponent=2): return number ** exponent print(power(3)) print(power(3, 3))

In [38]:

# Example 3 : Function that takes in a list of numbers and returns the sum of the even numbers in the list
def sum_of_even_numbers(numbers):
    even_sum = 0
    for number in numbers:
        if number % 2 == 0:
            even_sum += number
    return even_sum

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print(sum_of_even_numbers(numbers))

# Example 3 : Function that takes in a list of numbers and returns the sum of the even numbers in the list def sum_of_even_numbers(numbers): even_sum = 0 for number in numbers: if number % 2 == 0: even_sum += number return even_sum numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] print(sum_of_even_numbers(numbers))

30

In [39]:

# Example 4 : Function that takes in a string and returns a new string with all the vowels removed
def remove_vowels(string):
    vowels = ['a', 'e', 'i', 'o', 'u']
    new_string = ''
    for char in string:
        if char.lower() not in vowels:
            new_string += char
    return new_string

print(remove_vowels("Hello World"))

# Example 4 : Function that takes in a string and returns a new string with all the vowels removed def remove_vowels(string): vowels = ['a', 'e', 'i', 'o', 'u'] new_string = '' for char in string: if char.lower() not in vowels: new_string += char return new_string print(remove_vowels("Hello World"))

Hll Wrld

In [40]:

# Example 5 : Function that takes in a list of numbers and a number, and returns a new list with all the numbers in the original list that are greater than the given number
def filter_numbers(numbers, number):
    filtered_numbers = []
    for num in numbers:
        if num > number:
            filtered_numbers.append(num)
    return filtered_numbers

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print(filter_numbers(numbers, 5)) # Output: [6, 7, 8, 9, 10]

# Example 5 : Function that takes in a list of numbers and a number, and returns a new list with all the numbers in the original list that are greater than the given number def filter_numbers(numbers, number): filtered_numbers = [] for num in numbers: if num > number: filtered_numbers.append(num) return filtered_numbers numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] print(filter_numbers(numbers, 5)) # Output: [6, 7, 8, 9, 10]

[6, 7, 8, 9, 10]

Modules and Libraries¶

In [41]:

# Using the math module to perform mathematical operations

import math

# Using the sqrt function from the math module
print(math.sqrt(16))

# Using the pi constant from the math module
print(math.pi)

# Using the math module to perform mathematical operations import math # Using the sqrt function from the math module print(math.sqrt(16)) # Using the pi constant from the math module print(math.pi)

4.0
3.141592653589793

In [43]:

# Using the random module to generate random numbers:

import random

# Generating a random integer between 1 and 10
print(random.randint(1, 10))

# Generating a random float between 0 and 1
print(random.random())

# selecting a random item from a list
my_list = [1, 2, 3, 4, 5]
print(random.choice(my_list))

# Using the random module to generate random numbers: import random # Generating a random integer between 1 and 10 print(random.randint(1, 10)) # Generating a random float between 0 and 1 print(random.random()) # selecting a random item from a list my_list = [1, 2, 3, 4, 5] print(random.choice(my_list))

1
0.7110608023753344
4

Exception Handling¶

In [ ]:

# Example 1: Using a try-except block

try:
    # code that might raise an exception
    result = 1 / 0
except ZeroDivisionError:
    # code to handle the exception
    print("Cannot divide by zero.")

# Example 1: Using a try-except block try: # code that might raise an exception result = 1 / 0 except ZeroDivisionError: # code to handle the exception print("Cannot divide by zero.")

In [ ]:

# Example 2: Using the "raise" keyword

def divide(a, b):
    if b == 0:
        raise ValueError("Cannot divide by zero.")
    return a / b

try:
    result = divide(1, 0)
except ValueError as e:
    print(e)

# Example 2: Using the "raise" keyword def divide(a, b): if b == 0: raise ValueError("Cannot divide by zero.") return a / b try: result = divide(1, 0) except ValueError as e: print(e)

In [ ]:

# Example 3: Using an "else" block with a try-except block

try:
    # code that might raise an exception
    result = 1 / 2
except ZeroDivisionError:
    # code to handle the exception
    print("Cannot divide by zero.")
else:
    # code to run if no exception was raised
    print(result)

# Example 3: Using an "else" block with a try-except block try: # code that might raise an exception result = 1 / 2 except ZeroDivisionError: # code to handle the exception print("Cannot divide by zero.") else: # code to run if no exception was raised print(result)

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