abs(), pow(), round(), min(), max(), sum()) to perform numerical calculations.len(), .upper(), .lower(), .title(), .replace(), .strip(), .count(), .join()) to manipulate text.help() function and consult official Python documentation.In the previous section, we introduced basic arithmetic operators (such as +, -, *, /, and **). Operators are shorthand symbols for basic actions.
However, Python also includes a rich set of built-in functions. Built-in functions are pre-written pieces of code always available in Python without requiring any additional modules to be imported.
Python provides built-in tools and official documentation so you can discover how functions work and what arguments they accept.
help() Function: In Python, you can pass any function name into help() to view its description, parameters, and usage guidelines directly in your notebook or console.Help on built-in function round in module builtins:
round(number, ndigits=None)
Round a number to a given precision in decimal digits.
The return value is an integer if ndigits is omitted or None. Otherwise
the return value has the same type as the number. ndigits may be negative.
Python handles two primary numerical data types: - Integers (int): Whole numbers without decimals (e.g. 10, -5, 0). - Floating-point numbers (float): Numbers with a decimal point (e.g. 200.5, 4.0, -0.75).
| Built-in Function | Description | Example Syntax | Result |
|---|---|---|---|
abs(x) |
Returns the absolute (positive) value of x |
abs(-15) |
15 |
pow(base, exp) |
Raises base to the power of exp |
pow(3, 4) |
81 |
round(x, n) |
Rounds x to n decimal places |
round(3.14159, 2) |
3.14 |
max(a, b, c...) |
Returns the largest item | max(10, 20, 5) |
20 |
min(a, b, c...) |
Returns the smallest item | min(10, 20, 5) |
5 |
sum(iterable) |
Returns the total of all items in a collection | sum([10, 20, 30]) |
60 |
[] with sum()?
You might notice that we write sum([10, 20, 30]) with square brackets [] instead of sum(10, 20, 30).
In Python, square brackets [] create a list (a single container holding multiple items). The sum() function is specifically designed to take one single argument containing a collection of numbers (an iterable), rather than multiple separate arguments.
If you try running sum(10, 20, 30), Python will return an error because it expects a collection! Functions like max(10, 20, 30) and min(10, 20, 30), on the other hand, accept multiple separate arguments.
Strings (str) represent text data in Python.
0.len()) and specific string methods (like .upper(), .lower(), .replace()) to work with text.len("hello")..): "hello".upper().You can consult the Official Python String Methods Documentation or use help(str) in Python to see all available methods.
| Built-in Function / Method | Purpose | Example | Result |
|---|---|---|---|
len(text) |
Returns the number of characters | len("London") |
6 |
text.upper() |
Converts text to uppercase | "hello".upper() |
"HELLO" |
text.lower() |
Converts text to lowercase | "HELLO".lower() |
"hello" |
text.title() |
Converts text to title case | "alice smith".title() |
"Alice Smith" |
text.strip() |
Removes leading and trailing whitespace | " text ".strip() |
"text" |
text.replace(old, new) |
Replaces occurrences of a substring | "cat".replace("c", "b") |
"bat" |
text.count(sub) |
Counts occurrences of a substring | "banana".count("a") |
3 |
delimiter.join(iterable) |
Joins a list of strings into one string | ", ".join(["A", "B", "C"]) |
"A, B, C" |
[] with .join()?
Similar to sum(), the .join() string method joins multiple strings together. It expects a single collection of strings as its input. Square brackets [] create a list containing those strings:
# Sample text
greeting = " welcome to python programming! "
# Cleaning whitespace with .strip()
clean_greeting = greeting.strip()
print("Cleaned text:", clean_greeting)
# Getting length with len()
print("Length of cleaned text:", len(clean_greeting))
# Formatting text with .title()
print("Title case:", clean_greeting.title())
# Replacing text with .replace()
print("Replaced text:", clean_greeting.replace("programming", "coding"))
# Counting occurrences with .count()
print("Count of letter 'o':", clean_greeting.count("o"))Cleaned text: welcome to python programming!
Length of cleaned text: 30
Title case: Welcome To Python Programming!
Replaced text: welcome to python coding!
Count of letter 'o': 4An f-string (short for formatted string literal) allows you to embed variables and Python expressions directly inside a string text.
f or F before the opening quote.{} wherever you want their evaluated values to appear.When Python evaluates an f-string, it calculates whatever is inside {} and formats it as text.
You ordered 2 x woollen jumper at £45.00 each.You can also run simple mathematical calculations or string operations directly inside the {} brackets:
Total payable: £90.00
Item name in capital letters: WOOLLEN JUMPERStrings in Python are immutable, meaning they cannot be changed after they are created. When a string is modified, such as through concatenation or other operations, Python creates a new string object instead of altering the original one. Because of this, repeatedly building strings using operations like + in loops can be inefficient in both time and memory, since many intermediate string objects may be created. Python automatically manages memory using a process called garbage collection, which is how it reclaims memory from objects that are no longer needed. More specifically, garbage collection removes objects that are no longer reachable in the program—meaning there are no variable names or references pointing to them anymore, either because they were reassigned or deleted. In most cases, you do not need to manage this process manually. Instead, for efficiently building large strings, it is better to use tools designed for this purpose, such as ''join() or io.StringIO, which reduce the number of temporary string objects created.
Level:
Given the following variable assignments:
Write a script to display the data type of each variable using Python’s built-in type() function.
Level:
Given the variables a = 10, b = 200.5, c = 15, d = 3, and e = 4.0, answer the following questions using built-in functions:
a, b, and c using sum().a, b, c, d, and e using max().a, b, c, d, and e using min().pow().-42.75 using abs().1. Sum: 225.5
2. Max: 200.5
3. Min: 3
4. Pow: 81.0
5. Absolute: 42.75Level:
A weather station in Cambridge recorded daily maximum temperatures (°C) over five days as follows: 14.2, 16.8, 12.5, 18.1, and 15.0.
Write a Python script using built-in functions to: 1. Find the lowest recorded temperature using min(). 2. Find the highest recorded temperature using max(). 3. Calculate the average temperature by taking the sum() of the temperatures and dividing by the count (5). 4. Round the average temperature to 1 decimal place using round().
temperatures = [14.2, 16.8, 12.5, 18.1, 15.0]
lowest_temp = min(temperatures)
highest_temp = max(temperatures)
avg_temp = sum(temperatures) / len(temperatures)
rounded_avg = round(avg_temp, 1)
print("Lowest Temperature:", lowest_temp, "°C")
print("Highest Temperature:", highest_temp, "°C")
print("Average Temperature (raw):", avg_temp, "°C")
print("Average Temperature (rounded):", rounded_avg, "°C")Lowest Temperature: 12.5 °C
Highest Temperature: 18.1 °C
Average Temperature (raw): 15.319999999999999 °C
Average Temperature (rounded): 15.3 °CLevel:
Write a Python script to perform the following steps on the string text = " data science and analytics ":
help(str.strip) or consult documentation to understand what .strip() does, then remove the leading and trailing spaces from text..upper()."a" appears in the cleaned string using .count()."analytics" with "machine learning" using .replace().len().text = " data science and analytics "
# Step 1: Strip whitespace
clean_text = text.strip()
# Step 2: Uppercase
upper_text = clean_text.upper()
# Step 3: Count letter 'a'
count_a = clean_text.count("a")
# Step 4: Replace word
replaced_text = clean_text.replace("analytics", "machine learning")
# Step 5: Measure length
final_length = len(replaced_text)
print("Cleaned text:", clean_text)
print("Uppercase:", upper_text)
print("Count of 'a':", count_a)
print("Replaced text:", replaced_text)
print("Final length:", final_length)Cleaned text: data science and analytics
Uppercase: DATA SCIENCE AND ANALYTICS
Count of 'a': 5
Replaced text: data science and machine learning
Final length: 33Level:
["apples", "bananas", "cherries"]..join() method with ", " as the separator to combine these words into a single comma-separated string..title()."Shopping List: Apples, Bananas, Cherries".These exercises are slightly more difficult and will use all you have learnt so far in the course. In real-world applications, specifications are described in plain language. Practice converting verbal instructions into Python code using numerical functions, string methods, and f-strings.
Level:
Scenario: A customer visits a shop in Manchester and purchases three items: - A winter coat priced at £85.50 - A pair of leather shoes priced at £45.00 - A woollen scarf priced at £15.25
Write a Python script that carries out the following steps:
sum() function.0.15) and round it to 2 decimal places using round()."alexander smith" into proper title case using .title()."Manchester High Street Branch" using len().# Step 1: Prices
coat = 85.50
shoes = 45.00
scarf = 15.25
# Step 2: Sum using sum() with a list
original_total = sum([coat, shoes, scarf])
# Step 3: Discount calculation and rounding
raw_discount = original_total * 0.15
discount = round(raw_discount, 2)
# Step 4: Final amount
final_payable = original_total - discount
# Step 5: Name formatting
customer_name = "alexander smith".title()
# Step 6: Store name length
store_name = "Manchester High Street Branch"
store_len = len(store_name)
# Step 7: Formatted receipt
receipt = (
f"=== RECEIPT FROM {store_name.upper()} ===\n"
f"Store Name Character Length: {store_len}\n"
f"Customer: {customer_name}\n"
f"----------------------------------------\n"
f"Original Total: £{original_total:.2f}\n"
f"15% Loyalty Discount: -£{discount:.2f}\n"
f"Final Total Payable: £{final_payable:.2f}\n"
f"----------------------------------------"
)
print(receipt)=== RECEIPT FROM MANCHESTER HIGH STREET BRANCH ===
Store Name Character Length: 29
Customer: Alexander Smith
----------------------------------------
Original Total: £145.75
15% Loyalty Discount: -£21.86
Final Total Payable: £123.89
----------------------------------------Level:
Scenario: An event manager in Oxford needs to process attendee registrations for a conference.
The attendee details entered into the system are messy: - Name entered: " DR. ELEANOR VANCE " - Ticket category: "VIP PASS" - Base ticket price: £120.00 - Booking fee: £7.50 - Discount code applied deduction: £15.00
Write a Python script to: 1. Clean the attendee name by removing extra whitespace with .strip() and converting it to title case with .title(). 2. Calculate the net ticket price by taking the base price plus booking fee minus discount. 3. Find the lowest and highest values among the price components (base price, booking fee, discount deduction) using min() and max(). 4. Use len() to count the number of characters in the cleaned attendee name. 5. Produce a clean confirmation summary using an f-string.
# Messy input variables
raw_name = " DR. ELEANOR VANCE "
category = "VIP PASS"
base_price = 120.00
booking_fee = 7.50
discount_deduction = 15.00
# Step 1: Clean name
clean_name = raw_name.strip().title()
# Step 2: Net price
net_price = base_price + booking_fee - discount_deduction
# Step 3: Min and Max values among components
lowest_component = min(base_price, booking_fee, discount_deduction)
highest_component = max(base_price, booking_fee, discount_deduction)
# Step 4: Name character length
name_length = len(clean_name)
# Step 5: Summary print
summary = (
f"=== EVENT REGISTRATION CONFIRMATION ===\n"
f"Attendee: {clean_name} ({name_length} characters)\n"
f"Category: {category}\n"
f"Base Price: £{base_price:.2f}\n"
f"Booking Fee: £{booking_fee:.2f}\n"
f"Discount Applied: -£{discount_deduction:.2f}\n"
f"----------------------------------------\n"
f"Total Paid: £{net_price:.2f}\n"
f"Component Range: Lowest = £{lowest_component:.2f}, Highest = £{highest_component:.2f}"
)
print(summary)=== EVENT REGISTRATION CONFIRMATION ===
Attendee: Dr. Eleanor Vance (17 characters)
Category: VIP PASS
Base Price: £120.00
Booking Fee: £7.50
Discount Applied: -£15.00
----------------------------------------
Total Paid: £112.50
Component Range: Lowest = £7.50, Highest = £120.00abs(), pow(), round(), min(), max(), sum(), and len()) are built directly into Python.help(function_name) or check the Python Official Documentation to learn how functions work.sum() and string methods like .join() expect an iterable (such as a list denoted with [])..upper(), .lower(), .title(), .strip(), .replace(), and .count() allow for text formatting and cleaning.