PyAnWin/Python Control Flow and Iteration

Python Control Flow and Iteration

Python utilizes common control flow statements and iteration tools to execute code conditionally and repetitively.

if Statements

The basic if statement checks a condition and executes code if the condition is True:

 if x > 0: print("x is positive")

You can add an else block that executes when the condition is False:

 if x > 0: print("x is positive") else: print("x is negative or zero")

Exercise: Write an if/else statement that prints "Even" if a number is even and "Odd" if a number is odd.

elif Statements

The elif statement allows you to check multiple conditions. Code is executed on the first condition that evaluates to True:

 if x > 0: 
    print("x is positive")
elif x < 0:
        print("x is negative")
else:
    print("x is zero")

You can chain together as many elif blocks as you need.

Exercise: Write an if/elif/else chain that prints "Positive" for numbers > 0, "Negative" for numbers < 0 and "Zero" for 0.

for Loops

for loops iterate over sequences like lists, tuples and strings:

 fruits = ["apple", "banana", "orange"] 
for fruit in fruits:
    print(fruit)

The loop variable takes on the value of each element in the sequence in turn. You can also loop over ranges of numbers:

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

This will print 0 through 4.

Exercise: Write a for loop to print the numbers 1 to 10.

while Loops

while loops execute as long as a condition remains True:

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

The condition is checked each iteration. count += 1 prevents an infinite loop by incrementing count each time.

Here are some exercises without assessments for control flow and iteration in Python:

Exercise 1:

Write an if/else statement that prints "Even" if a number is even and "Odd" if a number is odd.

Exercise 2:

Write an if/elif/else chain that prints "Positive" for numbers > 0, "Negative" for numbers < 0 and "Zero" for 0.

Exercise 3:

Write a for loop to print the numbers 1 to 10.

Exercise 4:

Write a while loop that prints the numbers from 1 to 20 that are divisible by 3.

Exercise 5:

Given a list of integers, use a for loop to print only the even numbers in the list.

Exercise 6:

Use a while loop to print a countdown from 10 to 1.

Exercise 7:

Write a for loop that iterates over a string and prints each character.

Exercise 8:

Use break and continue statements inside a for loop that iterates from 1 to 10. break on the iteration for 5 and continue on the iteration for 7.

Let me know if you need me to provide sample solutions for these exercises without assessments. I can also come up with more exercises to help reinforce these concepts.