Course Content

Introduction to Python

1. First Acquaintance

The Very First Steps Comments Some Simple Math More Challenging Math Challenge Bringing It All Together

2. Variables and Types

Storing Numbers Naming Rules Using Variables Data Types Numbers Challenge Storing Text String Indexing Negative Indexing and Length String Slicing Challenge Concatenation

3. Conditional Statements

Boolean Data Type Challenge: Comparison Operators Combining Conditions Challenge: Logical Operators Membership Operators and Types Comparison Simple if/else Expressions Challenge: Grocery Store Challenge: Odd and Even if/elif/else Expressions Challenge: Grocery Store 2 Challenge: Positive, Negative or Zero

4. Other Data Types

What Is a List?List Methods Challenge Nested Lists Challenge What Is a Tuple?Tuple Methods Challenge Nested Tuples Challenge What Is a Dictionary?Challenge Dictionary Methods Challenge

5. Loops

while Loop Challenge for Loop Challenge Range Challenge Iterating Over Indexes Nested Loops

6. Functions

Built-in Functions Challenge Defining Your First Function Challenge if/else Statements in Functions Challenge Functions With No Return Challenge Modifying Functions Challenge Lambda Functions Challenge

Introduction to Python

Nested Lists

As mentioned in the opening chapter, lists in Python can store various data types, even including other lists. What's unique about Python, compared to many other programming languages, is that these nested lists can differ in length. Let's dive into an example. Imagine we have data about countries and their respective areas. Instead of jamming all that information into a single list, it would be more organized to have a distinct list for each country.

As illustrated, every country has its dedicated list nested within the primary list. Now, you might wonder, how do we navigate through such a structure? If we're dealing with a two-dimensional list, its elements are also lists. And, we can access the inner list's items using indexing. Consider a two-dimensional list named countries_2d that contains 3 main elements (which are lists). Each of these lists has 2 items. So, countries_2d[1] fetches the second list in the main list (keep in mind, Python indexing begins at 0). Moreover, countries_2d[1][0] retrieves the first item within that second list. Check out the example below for clarity.

Everything was clear?

Section 4. Chapter 4