Python Programming: Built‑in Functions, Strings, and the `math` Module

For English‑speaking students | max, min, abs, len, string ops, and math utilities

Laboratory Works (2.1 – 2.10)

Each lab includes a step‑by‑step algorithm, solution code, and expected output. Max score: 1.0 per lab.

Lab 2.1 – Maximum and Minimum of Three Numbers (no built‑ins)

Score: 0.2

Task: Write a program that reads three numbers and prints their maximum and minimum without using max() and min() (to practice conditional statements).

📌 Algorithm

Read three numbers from the user.
Use if/elif/else to find the maximum by comparing each pair.
Use a similar approach to find the minimum.
Print both results.

💻 Solution Code


a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
c = int(input("Enter third number: "))

# Find maximum
if a >= b and a >= c:
    maximum = a
elif b >= a and b >= c:
    maximum = b
else:
    maximum = c

# Find minimum
if a <= b and a <= c:
    minimum = a
elif b <= a and b <= c:
    minimum = b
else:
    minimum = c

print("Maximum:", maximum)
print("Minimum:", minimum)

📤 Expected Output

Enter first number: 5
Enter second number: 12
Enter third number: 8
Maximum: 12
Minimum: 5

📖 Step‑by‑Step Explanation

Read three numbers from the user.
Use if/elif/else to find the maximum by checking each possibility.
Use the same approach to find the minimum.
Print both results.

Lab 2.2 – Using Built‑in Functions `max()` and `min()`

Score: 0.2

Task: Write a program that reads three numbers and prints their maximum and minimum using max() and min().

📌 Algorithm

Read three numbers.
Use max(a, b, c) to find the maximum directly.
Use min(a, b, c) to find the minimum directly.
Print both results.

💻 Solution Code

a = int(input("Enter first number: "))
b = int(input("Enter second number: "))
c = int(input("Enter third number: "))

print("Maximum:", max(a, b, c))
print("Minimum:", min(a, b, c))

📤 Expected Output

Enter first number: 5
Enter second number: 12
Enter third number: 8
Maximum: 12
Minimum: 5

📖 Step‑by‑Step Explanation

Read three numbers.
max() returns the largest value among the arguments.
min() returns the smallest value.
Print the results.

Lab 2.3 – Absolute Value Sum

Score: 0.2

Task: Write a program that reads 5 numbers and prints the sum of their absolute values.

📌 Algorithm

Read numbers.
Compute the sum of absolute values.
Print the result.

💻 Solution Code

a = float(input("Enter number 1: "))
b = float(input("Enter number 2: "))
c = float(input("Enter number 3: "))
d = float(input("Enter number 4: "))
e = float(input("Enter number 5: "))

result = abs(a) + abs(b) + abs(c) + abs(d) + abs(e)
print(result)

📤 Expected Output

Enter number 1: -5
Enter number 2: 3
Enter number 3: -2
Enter number 4: 7
Enter number 5: -1
Sum of absolute values: 18

Lab 2.4 – String Concatenation

Score: 0.2

Task: Write a program that reads a first name and a last name, then prints a greeting.

📌 Algorithm

Read first name and last name.
Use concatenation to build the greeting string.
Print the result.

💻 Solution Code

first = input("Enter first name: ")
last = input("Enter last name: ")

greeting = "Hello " + first + " " + last + "! Welcome to Python!"
print(greeting)

📤 Expected Output

Enter first name: John
Enter last name: Smith
Hello John Smith! Welcome to Python!

📖 Step‑by‑Step Explanation

Read first name and last name.
Concatenate strings using + to form the greeting.
Print the complete greeting.

Lab 2.5 – String Length and Repetition

Score: 0.2

Task: Write a program that reads a string and prints a border of * characters around it.

📌 Algorithm

Read the word.
Calculate its length using len().
Print a top border of stars: '*' * (length + 8).
Print the word with stars on both sides: '* ' + word + ' *'.
Print a bottom border of stars (same as top).

💻 Solution Code

word = input("Enter a word: ")
length = len(word)

print('*' * (length + 8))
print('*   ' + word + '     *')
print('*' * (length + 8))

📤 Expected Output

Enter a word: Python
****************
*   Python     *
****************

📖 Step‑by‑Step Explanation

Read the word and compute its length.
Print a top border of stars using repetition.
Print the word padded with spaces and stars.
Print a bottom border identical to the top.

Lab 2.6 – Checking Substring with `in`

Score: 0.2

Task: Write a program that checks if a string contains the letter 'e'.

📌 Algorithm

Read the input string.
Use in to check if 'e' is in the string.
Print the appropriate message.

💻 Solution Code

s = input("Enter a string: ")

if 'e' in s:
    print("The string contains the letter 'e'")
else:
    print("The string does not contain the letter 'e'")

📤 Expected Output

Enter a string: Hello
The string contains the letter 'e'

📖 Step‑by‑Step Explanation

Read the input string.
Use in to test membership of 'e'.
Print a message based on the result.

Lab 2.7 – Vowel Checker

Score: 0.2

Task: Write a program that checks if a character is a vowel using in.

📌 Algorithm

Read the character.
Check that it's a single character.
Use in to check if it's in the set of vowels ('aeiouAEIOU').
Print the result.

💻 Solution Code

char = input("Enter a character: ")

if len(char) == 1 and char in 'aeiouAEIOU':
    print("Vowel")
else:
    print("Not a vowel")

📤 Expected Output

Enter a character: a
Vowel

📖 Step‑by‑Step Explanation

Read the character.
Ensure it's a single character with len().
Use in to test against the string of vowels.
Print the result.

Lab 2.8 – Using the `math` Module – Circle Area

Score: 0.2

Task: Write a program that reads the radius of a circle and calculates its area and circumference.

Formulas: Area = π × r², Circumference = 2 × π × r

📌 Algorithm

Import the math module.
Read the radius.
Calculate the area using math.pi.
Calculate the circumference using math.pi.
Print both results.

💻 Solution Code

import math

radius = float(input("Enter radius: "))

area = math.pi * radius ** 2
circumference = 2 * math.pi * radius

print("Area:", area)
print("Circumference:", circumference)

📤 Expected Output

Enter radius: 5
Area: 78.53981633974483
Circumference: 31.41592653589793

📖 Step‑by‑Step Explanation

Import the math module to access pi.
Read the radius as a float.
Compute area and circumference using math.pi.
Print the results.

Lab 2.9 – Using `math.sqrt()` – Euclidean Distance

Score: 0.2

Task: Write a program that reads two points (x1, y1) and (x2, y2) and calculates the distance between them.

Formula: distance = sqrt((x2-x1)² + (y2-y1)²)

📌 Algorithm

Import math.
Read the coordinates of both points.
Calculate the differences in x and y.
Use math.sqrt() to calculate the distance.
Print the result.

💻 Solution Code

import math

x1 = float(input("Enter x1: "))
y1 = float(input("Enter y1: "))
x2 = float(input("Enter x2: "))
y2 = float(input("Enter y2: "))

dx = x2 - x1
dy = y2 - y1
distance = math.sqrt(dx ** 2 + dy ** 2)

print("Distance:", distance)

📤 Expected Output

Enter x1: 0
Enter y1: 0
Enter x2: 3
Enter y2: 4
Distance: 5.0

📖 Step‑by‑Step Explanation

Import math.
Read all four coordinates.
Compute the differences in x and y.
Apply the Euclidean distance formula using math.sqrt().
Print the distance.

Lab 2.10 – Using `math.ceil()` and `math.floor()`

Score: 0.2

Task: Write a program that reads a number and prints its ceiling and floor.

📌 Algorithm

Import math.
Read the number.
Use math.ceil() to round up.
Use math.floor() to round down.
Print both results.

💻 Solution Code

import math

num = float(input("Enter a number: "))

print("Ceiling:", math.ceil(num))
print("Floor:", math.floor(num))

📤 Expected Output

Enter a number: 3.7
Ceiling: 4
Floor: 3

📖 Step‑by‑Step Explanation

Import math.
Read a floating‑point number.
math.ceil() returns the smallest integer ≥ the number.
math.floor() returns the largest integer ≤ the number.
Print both.

✏️ Practice Exercises (Independent Work)

Try these on your own. Each practice includes a hint. Score: 0.5 each.

Practice 1 – Maximum of Four Numbers

Score: 0.5

Task: Write a program that reads 4 numbers and prints the maximum using max().

Enter number 1: 7
Enter number 2: 3
Enter number 3: 9
Enter number 4: 5
Maximum: 9

📖 Algorithm

Read four numbers.
Pass all four to max().
Print the result.

Practice 2 – Absolute Difference

Score: 0.5

Task: Write a program that reads two numbers and prints their absolute difference.

Enter first number: 5
Enter second number: 12
Absolute difference: 7

📖 Algorithm

Read two numbers.
Compute abs(a - b).
Print the result.

Practice 3 – String Length

Score: 0.5

Task: Write a program that reads a string and prints its length, and also repeats the string length times..

Enter a string: Hello World
Length: 11  Hello WorldHello WorldHello WorldHello WorldHello WorldHello WorldHello WorldHello WorldHello WorldHello WorldHello World

📖 Algorithm

Read a string.
Use len() to get its length.
Print the length.

Practice 4 – Greeting Generator

Score: 0.5

Task: Read a title, first name, and last name, then print a formal greeting.

Enter title: Mr
Enter first name: John
Enter last name: Smith
Mr John Smith, welcome to the course!

📖 Algorithm

Read title, first name, last name.
Concatenate with commas and welcome message.
Print the greeting.

Practice 5 – Password Strength Checker

Score: 0.5

Task: Check if a password contains !, @, or # using in.

Enter password: hello!123
Strong password

📖 Algorithm

Read the password.
Check if any of the special characters are present using or with in.
Print "Strong password" if any is present, else "Weak password".

Practice 6 – Contains Space

Score: 0.5

Task: Check if a string contains a space.

Enter a string: Hello World
Contains a space

📖 Algorithm

Read the string.
Use ' ' in s to test for space.
Print the appropriate message.

Practice 7 – Sector Calculations

Score: 0.5

Task: Read radius and central angle (in degrees), calculate area and arc length of a circular sector using math.pi and math.radians.

Formulas:
Area: 1/2 r² 0 (where θ in radians)
Arc length: L=rθ (where θ in radians)

Enter radius: 10
Enter angle (degrees): 45
Area: 39.269908169872416
Arc length: 7.853981633974483

📖 Algorithm

Import math.
Read radius (float) and angle_deg (float).
Convert angle to radians: math.radians.
Compute area = 0.5 * radius**2 * angle_rad
Compute arc_length = radius * angle_rad.
Print both.

Practice 8 – Pythagorean Theorem

Score: 0.5

Task: Read the two shorter sides and calculate the hypotenuse using math.sqrt().

Enter side a: 3
Enter side b: 4
Hypotenuse: 5.0

📖 Algorithm

Import math.
Read sides a and b.
Compute hypotenuse = math.sqrt(a**2 + b**2).
Print the result.

Practice 9 – Quadratic Equation (Discriminant)

Score: 0.5

Task: Calculate the discriminant D = b² - 4ac.

Enter a: 1
Enter b: -5
Enter c: 6
Discriminant: 1

📖 Algorithm

Read a, b, c.
Compute discriminant = b**2 - 4*a*c.
Print the discriminant.

Practice 10 – Factorial

Score: 0.5

Task: Read n and calculate n! using math.factorial().

Enter n: 5
5! = 120

📖 Algorithm

Import math.
Read n as integer.
Compute math.factorial(n).
Print the result.

Practice 11 – Soccer Team Name

Score: 0.5

Task: Read a team name and print its length.

Enter team name: Barcelona
Barcelona has 9 characters

📖 Algorithm

Read team name.
Print the name and its length using len().

Practice 12 – City Names (shortest/longest)

Score: 0.5

Task: Read 3 city names and find the shortest and longest using min() and max() with key=len.

Enter city 1: Paris
Enter city 2: London
Enter city 3: Tokyo
Shortest: Paris
Longest: London

📖 Algorithm

Read three city names.
Use min(cities, key=len) for shortest.
Use max(cities, key=len) for longest.
Print both.

Practice 13 – Temperature Converter (round)

Score: 0.5

Task: Convert Celsius to Fahrenheit and round to 2 decimals using round().

Enter temperature in Celsius: 36.6
36.6°C = 97.88°F

📖 Algorithm

Read Celsius.
Compute Fahrenheit = C * 9/5 + 32.
Use round(F, 2) to format.
Print both.

Practice 14 – Email Validator (Part 1)

Score: 0.5

Task: Check if a string contains both @ and ..

Enter email: user@example.com
Valid

📖 Algorithm

Read email.
Check '@' in email and '.' in email.
Print "Valid" or "Invalid".

Practice 15 – Word Pattern

Score: 0.5

Task: Read a word and create a pattern with asterisks around it.

Enter a word: Hello
*******
*Hello*
*******

📖 Algorithm

Read the word.
Compute length.
Print top border: '*' * (length+6).
Print middle: '*' + ' ' + word + ' ' + '*'.
Print bottom border same as top.

🔑 Answer Key – Practice Exercises

Solutions for the independent practice exercises. Check your work after attempting them.

Practice 1 – Solution

a = int(input("Enter number 1: "))
b = int(input("Enter number 2: "))
c = int(input("Enter number 3: "))
d = int(input("Enter number 4: "))
print("Maximum:", max(a, b, c, d))

Practice 2 – Solution

a = float(input("Enter first number: "))
b = float(input("Enter second number: "))
print("Absolute difference:", abs(a - b))

Practice 3 – Solution

s = input("Enter a string: ")
print("Length:", len(s))

Practice 4 – Solution

title = input("Enter title: ")
first = input("Enter first name: ")
last = input("Enter last name: ")
greeting = title + " " + first + " " + last + ", welcome to the course!"
print(greeting)

Practice 5 – Solution

password = input("Enter password: ")
if '!' in password or '@' in password or '#' in password:
    print("Strong password")
else:
    print("Weak password")

Practice 6 – Solution

s = input("Enter a string: ")
if ' ' in s:
    print("Contains a space")
else:
    print("Does not contain a space")

Practice 7 – Solution

import math
radius = float(input("Enter radius: "))
area = math.pi * radius ** 2
circumference = 2 * math.pi * radius
print("Area:", area)
print("Circumference:", circumference)

Practice 8 – Solution

import math
a = float(input("Enter side a: "))
b = float(input("Enter side b: "))
c = math.sqrt(a ** 2 + b ** 2)
print("Hypotenuse:", c)

Practice 9 – Solution

a = float(input("Enter a: "))
b = float(input("Enter b: "))
c = float(input("Enter c: "))
discriminant = b ** 2 - 4 * a * c
print("Discriminant:", discriminant)

Practice 10 – Solution

import math
n = int(input("Enter n: "))
print(n, "! =", math.factorial(n))

Practice 11 – Solution

team = input("Enter team name: ")
print(team, "has", len(team), "characters")

Practice 12 – Solution

city1 = input("Enter city 1: ")
city2 = input("Enter city 2: ")
city3 = input("Enter city 3: ")
print("Shortest:", min(city1, city2, city3, key=len))
print("Longest:", max(city1, city2, city3, key=len))

Practice 13 – Solution

celsius = float(input("Enter temperature in Celsius: "))
fahrenheit = celsius * 9/5 + 32
print(celsius, "°C =", round(fahrenheit, 2), "°F")

Practice 14 – Solution

email = input("Enter email: ")
if '@' in email and '.' in email:
    print("Valid")
else:
    print("Invalid")

Practice 15 – Solution

word = input("Enter a word: ")
length = len(word)
print('*' * (length + 6))
print('*' + ' ' * 2 + word + ' ' * 2 + '*')
print('*' * (length + 6))

📋 Quick Reference – Built‑ins, Strings & math

Built‑in Functions

min(a,b,c) → smallest
max(a,b,c) → largest
abs(x) → absolute value
len(s) → string length
str(x) → convert to string

String Operations

"Hello" + " " + "World"  # concatenation
"Hi" * 3                 # repetition
len("Python")          # → 6
'e' in "Hello"         # → True

math Module

import math
math.sqrt(16)   # → 4.0
math.ceil(3.7) # → 4
math.floor(3.7) # → 3
math.factorial(5) # → 120
math.pi          # ≈ 3.14159

Module 1.3 - Built‑in Functions, Strings & math Module

Laboratory Works (2.1 – 2.10)

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

📌 Algorithm

💻 Solution Code

📤 Expected Output

✏️ Practice Exercises (Independent Work)

🔑 Answer Key – Practice Exercises

Practice 1 – Solution

Practice 2 – Solution

Practice 3 – Solution

Practice 4 – Solution

Practice 5 – Solution

Practice 6 – Solution

Practice 7 – Solution

Practice 8 – Solution

Practice 9 – Solution

Practice 10 – Solution

Practice 11 – Solution

Practice 12 – Solution

Practice 13 – Solution

Practice 14 – Solution

Practice 15 – Solution

📋 Quick Reference – Built‑ins, Strings & math

Built‑in Functions

String Operations

math Module