Control Structures

Python Logical Operators

• and: Returns True only if both conditions are True.
• or: Returns True if at least one condition is True.
• not: Reverses the logical value of a condition.

## LOGICAL OPERATORS EXAMPLE ##
a = True
b = False

print(a and b)
print(a or b)
print(not a)

False
True
False

Common Comparison Operators

• Equal to: ==
• Not equal to: !=
• Greater than: >
• Greater than or equal to: >=
• Less than: <
• Less than or equal to: <=

## COMPARISON OPERATORS EXAMPLE ##
age = 18

print(age == 21)
print(age != 21)
print(age > 18)
print(age >= 18)
print(age < 21)
print(age <= 21)

False
True
False
True
True
True

if Statement

The if statement is the most basic conditional statement. It executes a block of code only if a specified condition is True.

## IF STATEMENT EXAMPLE ##
age = 18

if age >= 18:
    print("You are eligible to vote.")

if-else Statement

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

## IF-ELSE STATEMENT EXAMPLE ##
weather = "sunny"

if weather == "rainy":
    print("Don't forget your umbrella.")
else:
    print("Enjoy the sunny day!")

if-elif-else Statement

The if-elif-else statement allows you to check multiple conditions and execute different code blocks based on the first condition that is True.
Note: The else is not required to use an elif.

## IF-ELIF-ELSE STATEMENT EXAMPLE ##
grade = 85

if grade >= 90:
    print("Excellent!")
elif grade >= 80:
    print("Good job!")
else:
    print("Needs improvement.")

Nested Conditional Statement

You can also nest conditional statements within each other to create more complex decision-making structures.

## NESTED CONDITIONAL STATEMENT EXAMPLE ##
age = 40

if age >= 18:
    if age >=35:
		print("You can vote and run for president!")
	else:
		print("You can vote.")
else:
    print("You're too young to vote.")

for element in sequence:
    # Code executed for each element

• for element in sequence: This part specifies the variable (element) that will hold the current value during each iteration, and the sequence of values to iterate over.
• # Code executed for each element: This block of code will be executed once for each element in the sequence.
• The for loop continues to execute as long as there are elements left in the sequence.
• You can use any valid variable name for the element.
• The range() function is commonly used to create a sequence of numbers.
• You can use the break statement to exit the loop prematurely, and the continue statement to skip the current iteration and proceed to the next one.

## RANGE OF NUMBERS EXAMPLE ##
for num in range(5):
    print(num)

## LIST EXAMPLE ##
fruits = ["apple", "banana", "orange"]

for fruit in fruits:
    print(fruit)

## STRING EXAMPLE ##
for character in "hello":
    print(character)

## BREAK & CONTINUE EXAMPLE ##
for num in range(20):
	if num==10:
		break
	elif num%2==0:
		continue
    print(num)

while condition:
    # Code executed each iteration

• while condition: This part specifies the condition that must be True for the loop to continue executing.
• # Code executed each iteration: This block of code will be executed repeatedly as long as the condition remains True.
• The while loop continues to execute as long as the specified condition is True.
• It's essential to ensure that the condition will eventually become False to avoid infinite loops.
• You can use the break statement to exit the loop prematurely, and the continue statement to skip the current iteration and proceed to the next one.

## WHILE LOOP EXAMPLE ##
count = 0

while count < 5:
	count += 1
	print(count)

## BREAK & CONTINUE EXAMPLE ##
num = 0

while True:
	num += 1
	if num > 10:
		break
	elif num%2 == 0:
		continue
	print(num)

1. Infinite Loop: The while True loop creates an infinite loop that will continue indefinitely unless explicitly broken.
2. Pre-Loop Code: The code before the condition check is executed once, before the loop's main body.
3. Condition Check: The if condition is evaluated. If the condition is true, the break statement is executed, and the loop terminates.
4. Loop Body: If the condition is false, the code within the loop body is executed.
5. Loop Repetition: The loop then repeats, going back to step 2.

## LOOP AND A HALF EXAMPLE ##
sentinel_value = -1
count = 0
quiz_sum = 0

while True:
	# Code to be executed before the loop's condition check
	score = int(input("Enter a number (-1 to quit): "))
	# Condition to check for loop termination
	if score == sentinel_value:
		break
	# Code to be executed repeatedly
	count +=1
	quiz_sum += score

print("Quiz Average:",round(quiz_sum/count,2))

Core Functions of Random:

• random.random(): Generates a random floating-point number between 0 and 1 (exclusive).
• random.randint(a, b): Generates a random integer between a and b (inclusive).
• random.randrange(start, stop[, step]): Generates a random integer from the range [start, stop), optionally skipping steps.
• random.choice(sequence): Returns a random element from a sequence (like a list, tuple, or string).

## RANDOM EXAMPLES ##
import random

random_float = random.random()
print(random_float)

random_int = random.randint(1, 10)
print(random_int)

random_even = random.randrange(2, 10, 2)
print(random_even)

fruits = ["apple", "banana", "cherry"]

random_fruit = random.choice(fruits)
print(random_fruit)