Conditional Statements

• Conditional statements in Python are used to make decisions based on conditions.

• These statements control the flow of execution depending on whether a condition evaluates to True or False.

Types of Conditional Statements

1. if Statement

2. if-else Statement

3. if-elif-else Statement

if Statement

• The if statement executes a block of code if the condition is True.

    if condition:
        # Code to execute if condition is True
  

if-else Statement

• The if-else statement provides an alternative block of code to execute if the condition is False.

    if condition:
        # Code to execute if condition is True
    else:
        # Code to execute if condition is False
  

if-elif-else Statement

• The if-elif-else statement allows checking multiple conditions. Once a condition evaluates to True, the corresponding block is executed, and the remaining conditions are skipped.

    if condition1:
        # Code to execute if condition1 is True
    elif condition2:
        # Code to execute if condition2 is True
    else:
        # Code to execute if none of the conditions are True
  

Short-Hand Conditional Statements

One-Line if Statement

• You can write an if statement in one line.

    x = 10
    if x > 5: print("x is greater than 5")
  

Ternary Operator (Conditional Expression)

• A concise way to write if-else statements in one line.

    x = 10
    message = "x is greater than 5" if x > 5 else "x is not greater than 5"
    print(message)
  

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Loops

• Loops in Python are used to execute a block of code repeatedly as long as a condition is true or for a predefined number of iterations.

Types of Loops in Python

1. for Loop

2. while Loop

for Loop

• The for loop is used to iterate over a sequence (e.g., list, tuple, string, or range) or any iterable object.

    for variable in iterable:
        # Code to execute in each iterationWhile Loop
  

• Using range(): The range() function is commonly used with for loops to generate a sequence of numbers.

    # Print numbers from 0 to 4
    for i in range(5):
        print(i)
  

while Loop

• The while loop repeats a block of code as long as a condition is True.

    while condition:
        # Code to execute while the condition is True
  

Special Statements in Loops

• Python provides special statements to control the flow of loops:

1. break: Exits the loop prematurely.

    for i in range(5):
        if i == 3:
            break
        print(i)
    # Output: 0 1 2
   

2. continue: Skips the current iteration and moves to the next.

    for i in range(5):
        if i == 3:
            continue
        print(i)
    # Output: 0 1 2 4
   

3. pass: Does nothing; acts as a placeholder.

    for i in range(5):
        if i == 3:
            pass
        print(i)
    # Output: 0 1 2 3 4
   

Loops with else

• Both for and while loops can have an optional else block, which executes if the loop completes normally (without a break).

Example with for:

for i in range(5):
    print(i)
else:
    print("Loop completed successfully!")

Example with while:

i = 0
while i < 3:
    print(i)
    i += 1
else:
    print("Loop completed successfully!")