Lesson 3 - Control Flow

3.1 Conditional Statements

Control statements in Python help your program make decisions based on conditions using if, elif, and else blocks.

Conditional Operators:

Conditional operators allow you to compare values in Python:

Operator	Description	Example
==	Equal to	x == y
!=	Not equal to	x != y
>	Greater than	x > y
<	Less than	x < y
>=	Greater than or equal to	x >= y
<=	Less than or equal to	x <= y
in	Returns True if value is present in sequence	x in sequence
not in	Returns True if value is not present in sequence	x not in sequence

Example using if, elif, and else:

x = 10
if x > 0:
    print("Positive")
elif x == 0:
    print("Zero")
else:
    print("Negative")

In this example:

• x > 0 checks if x is greater than 0.
• x == 0 checks if x is exactly equal to 0.
• else covers any other case where x is negative.

Logical Operators:

Logical operators (and, or, not) allow you to combine multiple conditions:

Operator	Description	Example
and	Returns True if both operands are true	x and y
or	Returns True if either operand is true	x or y
not	Returns True if operand is false	not x

Example using Logical Operators:

x = 10
y = 10
if x == 10 and y == 10:
    print("Both x and y are equal to 10.")
elif x == 10 or y == 10:
    print("Either x or y equals 10.")
else:
    print("None of them equals 10.")

In this example:

• x == 10 and y == 10 checks if both x and y are equal to 10.
• x == 10 or y == 10 checks if either x or y (or both) equals 10.
• else covers any other cases where neither x nor y equals 10.

Try modifying the values of x and y in the examples above to see how the conditions and logical operators behave.