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

Combining Conditions

In Boolean logic, two fundamental operators are OR and AND. What do they represent? The OR operator checks if either of the conditions is true and returns True if so; otherwise, it returns False. The AND operator ensures both conditions are true before returning True. If not, it returns False. In Python, to combine conditions, use the and & or operators (always in lowercase). For example:

condition1 and condition2 yields True only when both conditions are True.
condition1 or condition2 gives True if at least one condition is True.

Note
You can also chain more than two conditions using these operators. Employ parentheses to clarify the order of operations.

As an illustration, consider these conditions:

Whether 2 exceeds 1 and if "bbb" isn't the same as "aaa".
If the character with index 2 in the string "my string" is either "y" or "s".

Code Description

In the first line of the code, 2 > 1 and "bbb" != "aaa" involves two conditions connected by the and operator. The first condition 2 > 1 is true because 2 is greater than 1. The second condition "bbb" != "aaa" is also true because the strings "bbb" and "aaa" are not equal. Since both conditions are true and they are connected by and, the entire expression evaluates to true.

In the second line, "my string"[2] == "y" or "my string"[2] == "s" checks two conditions connected by the or operator. The expression "my string"[2] refers to the third character of the string "my string", which is " ". The first condition "my string"[2] == "y" is false. The second condition "my string"[2] == "s" is false, and since both of the conditions is false and they are connected by or, the overall expression evaluates to false.

How should we interpret the outcomes? The initial print() issues a True response since both 2 > 1 and "bbb" != "aaa" hold true. The following print() yields False because the character at index 2 is neither 'y' nor 's' (it's actually a space).

Note
If you wish to reverse a boolean value, employ the not operator. For instance, not 1 == 1 results in False because 1 == 1 is True, and we've negated that to False.

What output does the subsequent code produce?

Select the correct answer

Code Description

print(0 > 10 and 5 > 2): This prints False because, while 5 > 2 is true, 0 > 10 is false. The and operator requires both conditions to be true, but since one is false, the overall expression is false.

print(2*2 == 5 or 1+1 != 3): This prints True because 2*2 == 5 is false, but 1+1 != 3 is true. The or operator only requires one of the conditions to be true for the overall expression to be true.

Everything was clear?

Section 3. Chapter 3