Built in functions

Objectives

• Understand the concept of built-in functions in Python.
• Learn how to use some commonly used built-in functions for math, strings, and basic input/output.
• Explore the purpose and usage of functions like print(), len(), input(), and more.

As well as creating our own functions Python comes with a wide range of built-in functions that perform various tasks, making programming easier and more efficient. These functions are part of Python's standard library and can be used without the need for additional installations.

There are a whole host of other functions available to us that can be either imported to our program e.g. the random library, or installed e.g. the pandas library. We'll consider this approach in a later section

Example 5

print("Welcome to the Built-in Functions Lesson!")
user_name = input("Enter your name: ")
print("Hello,", user_name)

sample_string = "Climate"
string_length = len(sample_string)
print("The length of the string is:", string_length)

value = input("Enter a whole number: ")
print(type(value))

value_int = int(value)
print(type(value))

number = -7.25
abs_number = abs(number)
print("The absolute value is:", abs_number)

decimal_number = 3.14159
rounded_number = round(decimal_number, 2)
print("The rounded value is:", rounded_number)

Before running this code, read it and predict what you think will be displayed for the following:

• line 2: What will input("Enter your name: ") do?
• line 6: What does the len function return for the string 'Climate'?
• line 10 and 13: what will be output from the type() function in both cases?
• line 16: What will be the result of abs(-7.25)?
• line 20: What will round(3.14159, 2) return?

Run the program in a Python environment and compare the actual output with your predictions.

Commonly Used Built-In Functions

Function	Description	Example	Output
print()	We have seen this used in previous sections. The print() function is used to display information on the screen. It can print text, variables, and the result of expressions.	print("Welcome")	"Welcome"
len()	The len() function returns the length of a string. It counts the number of characters in the string.	len("Hello")	5
input()	The input() function allows user input. It waits for the user to enter data and returns it as a string.
int()	used for data type conversion. int() converts a value to an integer
float()	used for data type conversion. float() converts a value to an real number
str()	The str() function converts other data types to strings
max()	used to find the maximum value among a set of values
min()	used to find the minimum value among a set of values.
abs()	The abs() function returns the absolute value of a number.
round()	The round() function rounds a floating-point number to the nearest integer
str.upper()	Converts characters in str variable to upper case
str.lower()	Converts characters in str variable to lower case
chr()	chr() converts an ASCII code (integer) to a character
ord()	ord() converts a character to its ASCII integer code

Activity

Copy and paste the following code into a code editor, before running the code read it and predict what you think the output will be. Then make changes to the code as indicated below.

print("Welcome to the Modified Built-in Functions Lesson!")
age = int(input("Enter your age: "))
print("You are", age, "years old.")

another_string = "Environmental Science"
string_upper = another_string.upper()
string_lower = another_string.lower()
print("Uppercase:", string_upper)
print("Lowercase:", string_lower)

float_number = float(input("Enter a decimal number: "))
rounded_float = round(float_number)
print("Rounded number:", rounded_float)

negative_number = int(input("Enter a negative integer: "))
absolute_value = abs(negative_number)
print("Absolute value:", absolute_value)

Make the following changes:

• Change the string and observe the output of the upper() and lower() methods.
• Input a decimal number and see the rounded result.
• Input a negative integer and see the absolute value.

Climate Quest Project

Throughout this topic we'll be working on a large scale project: Climate Quest. In this project a player embarks on a journey to combat the effects of climate change by making decisions that impact the environment. Each choice affects the outcome of the game, emphasizing the importance of individual actions in addressing climate change.

Go to task 5 - Built-in Functions

Questions

1. What is the primary purpose of the print() function in Python?

To perform mathematical calculations

To find the maximum value in a list

To display information on the screen

To convert data types

The print() function is used to output data to the console or terminal, allowing the user to see information or results generated by the program.

Submit

2. Which built-in function returns the length of a string?

size()

length()

count()

len()

The len() function in Python returns the number of characters in a string, or the number of items in a list, tuple, or other collection.

Submit

3. What does the input() function do in Python?

It performs rounding operations

It allows user input and returns it as a string

It calculates the absolute value of a number

It converts a value to uppercase

The input() function is used to prompt the user for input and returns that input as a string, which can then be processed or used in the program.

Submit

4. How can you convert a string containing a number, like 42, to an actual integer in Python?

Use the int() function

Use the str() function

Use the float() function

Use the round() function

The int() function converts a string representing a number into an integer, which can then be used in mathematical operations.

Submit

5. What does the max() function do in Python?

Returns the length of a string

Returns the maximum value among a set of values

Converts all characters to uppercase

Calculates the sum of all elements in a list

The max() function returns the largest item in an iterable or the largest of two or more arguments provided.

Submit

6. Which built-in function is used to find the absolute value of a number?

abs()

max()

round()

len()

The abs() function returns the absolute value of a number, which is the distance of the number from zero, without regard to whether it is positive or negative.

Submit

7. What does the round() function do to a floating-point number?

Converts it to an integer

Rounds it to the nearest integer

Converts it to a string

Finds its square root

The round() function rounds a floating-point number to the nearest integer, optionally specifying the number of decimal places to round to.

Submit

8. Which function is used to change all characters in a string to uppercase?

str.capitalize()

str.upper()

str.lower()

str.title()

The str.upper() method returns a new string where all the characters in the original string have been converted to uppercase.

Submit

9. What is the purpose of the chr() function in Python?

To find the length of a string

To calculate mathematical expressions

To convert a character to its integer representation

To perform character encoding

The chr() function returns the string representing a character whose Unicode code point is the integer passed. This is used to convert numbers back into their corresponding characters.

Submit

10. Which function is used to convert an integer to its corresponding character?

int.char()

chr()

char()

int.to_char()

The chr() function is used to convert an integer (representing a Unicode code point) into its corresponding character in Python.

Submit

Programming Tasks