Python Programming | JNTUA | UNIT 2 | Conditionals and Recursion |
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This document summarizes key concepts from lectures 9-11 on conditionals and recursion in Python programming. It discusses logical operators, relational operators, boolean expressions, floor division, modulus, conditional execution using if/else statements, chained and nested conditionals. Recursion is defined as a function calling itself and examples of valid and infinite recursion are provided. The document also covers taking keyboard input in Python using the input function.
Python Programming | JNTUA | UNIT 2 | Conditionals and Recursion |
- 1. Python Programming Unit – II (Part II) (Lecture 11) Conditionals and Recursion Recursion Infinite Recursion Keyboard input
- 2. Python Programming Unit – II (Part II) (Lecture 9) Conditionals and Recursion
- 3. Syllabus Lecture 9 Lecture 10 Lecture 11 Floor division and modulus Boolean expressions Logical operators Conditional execution Alternative execution Chained conditionals Nested conditionals Recursion Infinite Recursion Keyboard input
- 4. Syllabus Lecture 9 Floor division and modulus Boolean expressions Logical operators
- 5. • There are three logical operators: 1. and 2. or 3. not Relational operators: • A = = B(Equal to) • A! = B (Not equal to) • A > B (Greater than) • A < B (Less than) • A > = B (Greater than or equal to) • A < = B (Less than or equal to) A Boolean expression is either true or false. • Ex: A = 5, B = 5, C = 6 • A = = B returns True • A = = C returns False Floor division: • Digits after the decimal point are removed. • Symbol for Floor division: // • Ex: 9 / 2 is 4.5 (Division) 9 // 2 is 4 (Floor division) Modulus: • Returns the remainder value • Symbol for Modulus: % • Ex: 9 % 2 is 1 Floor division and modulus Boolean expressions Logical operators
- 6. • There are three logical operators: 1. and 2. or 3. not Relational operators: • A = = B(Equal to) • A! = B (Not equal to) • A > B (Greater than) • A < B (Less than) • A > = B (Greater than or equal to) • A < = B (Less than or equal to) A Boolean expression is either true or false. • Ex: A = 5, B = 5, C = 6 • A = = B returns True • A = = C returns False Floor division: • Digits after the decimal point are removed. • Symbol for Floor division: // • Ex: 9 / 2 is 4.5 (Division) 9 // 2 is 4 (Floor division) Modulus: • Returns the remainder value • Symbol for Modulus: % • Ex: 9 % 2 is 1 Floor division and modulus Boolean expressions Logical operators
- 7. Python Programming Unit – II (Part II) (Lecture 10) Conditionals and Recursion
- 8. Syllabus Lecture 9 Lecture 10 Lecture 11 Floor division and modulus Boolean expressions Logical operators Conditional execution Alternative execution Chained conditionals Nested conditionals Recursion Infinite Recursion Keyboard input
- 10. Conditional execution Alternative execution Chained conditionals Nested conditionals • Conditions change the flow of program execution • if statement is used in conditions Syntax: if condition: statement 1 … • Two possibilities (else is used) Syntax: if condition: statement 1 … else: statement 2 … • More than two possibilities. • elif is used. Syntax: if condition: statement 1 elif condition: statement 2 elif condition: statement 3 else: statement 4 • Another Condition in one condition Syntax: if condition1: if condition2: statement 1 else: statement 2 else: statement 3 Conditionals
- 11. Conditional execution Alternative execution Chained conditionals Nested conditionals • Conditions change the flow of program execution • if statement is used in conditions Syntax: if condition: statement 1 … • Two possibilities (else is used) Syntax: if condition: statement 1 … else: statement 2 … • More than two possibilities. • elif is used. Syntax: if condition: statement 1 elif condition: statement 2 elif condition: statement 3 else: statement 4 • Another Condition in one condition Syntax: if condition1: if condition2: statement 1 else: statement 2 else: statement 3
- 12. Python Programming Unit – II (Part II) (Lecture 11) Conditionals and Recursion
- 13. • There are three logical operators: 1. and 2. or 3. not Relational operators: • A = = B(Equal to) • A! = B (Not equal to) • A > B (Greater than) • A < B (Less than) • A > = B (Greater than or equal to) • A < = B (Less than or equal to) A Boolean expression is either true or false. • Ex: A = 5, B = 5, C = 6 • A = = B returns True • A = = C returns False Floor division: • Digits after the decimal point are removed. • Symbol for Floor division: // • Ex: 9 / 2 is 4.5 (Division) 9 // 2 is 4 (Floor division) Modulus: • Returns the remainder value • Symbol for Modulus: % • Ex: 9 % 2 is 1 Floor division and modulus Boolean expressions Logical operators
- 14. Conditional execution Alternative execution Chained conditionals Nested conditionals • Conditions change the flow of program execution • if statement is used in conditions Syntax: if condition: statement 1 … • Two possibilities (else is used) Syntax: if condition: statement 1 … else: statement 2 … • More than two possibilities. • elif is used. Syntax: if condition: statement 1 elif condition: statement 2 elif condition: statement 3 else: statement 4 • Another Condition in one condition Syntax: if condition1: if condition2: statement 1 else: statement 2 else: statement 3
- 15. Syllabus Lecture 9 Lecture 10 Lecture 11 Floor division and modulus Boolean expressions Logical operators Conditional execution Alternative execution Chained conditionals Nested conditionals Recursion Infinite Recursion Keyboard input
- 16. Lecture 11 Recursion Infinite Recursion Keyboard input Recursion
- 17. Recursion • Function to call itself Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n = n - 1 countdown(n) Countdown(n) n 4 If n < 0 False Print(n) n = n-1 Output: 4
- 18. Recursion • Function to call itself Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n = n - 1 countdown(n) Countdown(n) n 3 If n < 0 False Print(n) n = n-1 Call count down Output: 4 3
- 19. Recursion • Function to call itself Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n = n - 1 countdown(n) Countdown(n) n 2 If n < 0 False Print(n) n = n-1 Call count down Output: 4 3 2
- 20. Recursion • Function to call itself Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n = n - 1 countdown(n) Countdown(n) n 1 If n < 0 False Print(n) n = n-1 Call count down Output: 4 3 2 1
- 21. Recursion • Function to call itself Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n = n - 1 countdown(n) Countdown(n) n 0 If n < 0 False Print(n) n = n-1 Call count down Output: 4 3 2 1 0
- 22. Recursion • Function to call itself Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n = n - 1 countdown(n) Countdown(n) n -1 If n < 0 False Print(n) n = n-1 Call count down Output: 4 3 2 1 0 Blast Print(“Blast”) True
- 24. Countdown(n) n 4 If n < 0 False Print(n) n = n+1 Output: 4 Infinite Recursion • Making recursive calls forever • The program never terminates. Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) n=n+1 countdown(n)
- 25. Countdown(n) n 5 If n < 0 False Print(n) n = n+1 Call count down Output: 4 5 Infinite Recursion • Making recursive calls forever • The program never terminates. Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) countdown(n+1)
- 26. Countdown(n) n 6 If n < 0 False Print(n) n = n+1 Call count down Output: 4 5 6 Infinite Recursion • Making recursive calls forever • The program never terminates. Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) countdown(n+1)
- 27. Countdown(n) n 7 If n < 0 False Print(n) n = n+1 Call count down Output: 4 5 6 7 Infinite Recursion • Making recursive calls forever • The program never terminates. Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) countdown(n+1)
- 28. Countdown(n) n 8 If n < 0 False Print(n) n = n+1 Call count down Output: 4 5 6 7 8 Infinite Recursion • Making recursive calls forever • The program never terminates. Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) countdown(n+1)
- 29. Countdown(n) n 9 If n < 0 False Print(n) n = n+1 Call count down Output: 4 5 6 7 8 Infinite recursion Infinite Recursion • Making recursive calls forever • The program never terminates. Ex: def countdown(n): if n < 0: print (“Blast”) else: print (n) countdown(n+1)
- 31. Keyboard input • Accept input from the user with keyboard. • input function is used A = 5 B = 6 print( A + B ) is 11 Here A & B variables has fixed values (given in the program) A = int(input("enter a value:")) B = int(input("enter b value:")) print( A + B) Here A & B variables has no fixed values (given in runtime)