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

Naming Rules

As we discussed in the last chapter, variables are essential for holding values that we'll use later on. When naming variables in Python, there are some rules and best practices to keep in mind:

Variable names can include letters, numbers, or underscores:
- myVariable1
- number_2
- data_frame3
- Python4Life
- _underscoreVar
Variable names can't start with a number:
- variable1 (Correct)
- 1variable (Incorrect - starts with a number)
Variable names are case-sensitive:
- MyVariable and myvariable are different variables.
- Data and data are different variables.
- Number1 and number1 are different variables.
Apart from the underscore _, special characters aren't allowed:
- my_variable (Correct)
- my-variable (Incorrect - contains a hyphen)
- variable@name (Incorrect - contains an @)
- data*star (Incorrect - contains an asterisk *)
Reserved words in Python can't be used as variable names:
- forLoop (Correct - not a reserved word)
- ifCondition (Correct - not a reserved word)
- for (Incorrect - for is a reserved word)
- while (Incorrect - while is a reserved word)
- try (Incorrect - try is a reserved word)

Note
If you're uncertain about why a particular variable name is considered correct or incorrect, you can refer back to the above rules and examples for clarification.

Everything was clear?

Section 2. Chapter 2

Introduction to Python

Naming Rules

Which of these would be valid variable names in Python?

Select a few correct answers