Control Flow

Mastering if-else statements, loops (for, while), and understanding flow control.

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1. What is the purpose of an if-else statement in Python?

   age = 18
   if age >= 18:
       print("You are an adult.")
   else:
       print("You are a minor.")

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2

How do you use elif to check multiple conditions?

score = 85
if score >= 90:
    print("Grade: A")
elif score >= 80:
    print("Grade: B")
elif score >= 70:
    print("Grade: C")
else:
    print("Grade: D")

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3

How can you use nested if-else statements?

num = 15
if num > 10:
    if num % 2 == 0:
        print("Even number greater than 10")
    else:
        print("Odd number greater than 10")
else:
    print("Number 10 or less")

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4

What is the difference between break and continue in loops?

for i in range(5):
    if i == 2:
        continue  # Skip the rest of the loop for this iteration
    print(i)

for i in range(5):
    if i == 2:
        break  # Exit the loop
    print(i)

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5

How do you create a while loop that terminates when a condition is met?

count = 0
while count < 5:
    print(count)
    count += 1

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6

How can you use a for loop to iterate over a list?

fruits = ['apple', 'banana', 'cherry']
for fruit in fruits:
    print(fruit)

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7

What is the purpose of the else block in a loop?

for i in range(3):
    print(i)
else:
    print("Loop completed")

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8

How do you use a while loop with an else block?

count = 0
while count < 3:
    print(count)
    count += 1
else:
    print("While loop completed")

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9

How do you use the range function with a for loop?

for i in range(1, 5):
    print(i)

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10

How can you create an infinite while loop and terminate it using break?

while True:
    user_input = input("Type 'exit' to stop: ")
    if user_input == 'exit':
        break

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11

How can you use for loops with dictionaries?

student_scores = {'Alice': 85, 'Bob': 90, 'Charlie': 78}
for student, score in student_scores.items():
    print(f"{student}: {score}")

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12

How do you use if statements to check for even and odd numbers?

number = 7
if number % 2 == 0:
    print("Even")
else:
    print("Odd")

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13

How can you use while loops to perform an action until a condition is met?

num = 10
while num > 0:
    print(num)
    num -= 1

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14

How do you handle multiple conditions using logical operators in if statements?

temperature = 25
humidity = 60
if temperature > 20 and humidity > 50:
    print("Warm and humid")
else:
    print("Not warm or not humid")

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15

How can you use else in an if-else chain to handle a default case?

day = 'Monday'
if day == 'Saturday':
    print("It's the weekend!")
elif day == 'Sunday':
    print("It's the weekend!")
else:
    print("It's a weekday")

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16

How do you iterate over characters in a string using a for loop?

word = "hello"
for char in word:
    print(char)

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17

How can you use break to exit a for loop early?

for i in range(5):
    if i == 3:
        break
    print(i)

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18

How do you use continue to skip certain iterations in a loop?

for i in range(5):
    if i == 2:
        continue
    print(i)

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19

How can you check for membership in a list using if statements?

colors = ['red', 'blue', 'green']
if 'blue' in colors:
    print("Blue is in the list")
else:
    print("Blue is not in the list")

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20

How can you handle multiple loops with nested loops?

for i in range(2):
    for j in range(3):
        print(f"i={i}, j={j}")

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21

How can you use if statements to check if a number is positive, negative, or zero?

number = -5
if number > 0:
    print("Positive")
elif number < 0:
    print("Negative")
else:
    print("Zero")

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22

How do you use a for loop to iterate over a range with a specific step value?

for i in range(0, 10, 2):
    print(i)

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23

How can you use a while loop to count down from a specified number and stop when a specific condition is met?

count = 10
while count > 0:
    print(count)
    if count == 5:
        break
    count -= 1

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24

How can you use nested for loops to create a multiplication table?

for i in range(1, 6):
    for j in range(1, 6):
        print(f"{i} x {j} = {i * j}")
    print()  # New line for better readability

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25

How do you use list comprehensions with conditional statements?

numbers = [1, 2, 3, 4, 5]
squares = [x**2 for x in numbers if x % 2 == 0]
print(squares)  # Output will be [4, 16]

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