Python Basics: While Loops and Variables

Python Code Examples

• Example 1: Printing characters in a string

• x = "abcdef" and i = "a" are assigned

• A while loop prints "a" repeatedly until i is no longer in x

• Output: aaaa

• Example 2: Appending values to a list

• An empty list values is created

• A for loop appends numbers from 1 to 3 to values using range(1, 4)

• Output: [1, 2, 3]

Python Revision Tour

• Code example: Printing x and y values in a while loop
• x is initially 10, and y is initially 0
• The loop continues until x is no longer greater than y
• Output: x and y values decrementing and incrementing, respectively

Question 1: Correcting syntax errors

• Original code:
  • VAL and val mismatch in variable naming
  • Corrected code:
    • val is replaced with VAL throughout the code
    • Underlined corrections: VAL%4, VAL%5, and VAL+10

Question 2: Palindrome checker

• Original code: incomplete and cropped
• Corrected code:
  • str is assigned user input using input("enter any string")
  • length is calculated as the length of the input string
  • mid is calculated as half the length of the string
  • A loop checks if the string is a palindrome by comparing characters from the start and end
  • Output: "It is a palindrome" if the string meets the condition, otherwise "it is not a palindrome"

Prime Number Checker

• Function prime(n):
  • Takes an integer n as input
  • Loops through numbers from 2 to n/2
  • Checks if n is divisible by any number in the range
  • Prints "Number is not prime" if divisible, otherwise "Number is prime"

Printing Cubes of Numbers

• Code example:
  • Loops from 15 to 50 using range(15, 50)
  • Prints the cube of each number in the range

Printing "Hello" in a Loop

• Code example:
  • Initializes count to 0
  • A while loop continues until count reaches 10
  • Prints "Hello" and increments count in each iteration
  • Output: "Hello" printed 10 times