Python if/else Statement

1. Control Flow
2. if/else Statements

If-else statements are basically the decision-making control flow statements. They are also called conditional statements. Block of the code in different sections is executed based on the satisfaction of the condition.

Type of if-else statements are:

• python if statements

  if statements contain one conditional expression and block of code in its body. If the condition is satisfied then its body gets executed.

  Syntax

  
  if conditional expression:
      #body

  Example:

  
  name=input("Enter your name: ")
  if name=='harry'
     print("He is handsome")

  Output

  
  Enter your name: harry
  He is handsome.

• Python if-else statements

  In these conditional statements If statements contain one conditional expression and block of code in their body as well as in the else block. Then if the if-block condition satisfies then the if-block's code is executed otherwise else block's code is executed.

  Syntax

  
  if conditional expression:
      #if block body
  else:
      #else block body

  Example

  
  name=input("Enter your name: ")
  
  if name=='harry':
     print("He is handsome")
  else:
     print("He is not more handsome")
          

  Output

  
  Enter your name: harry
  He is handsome

• python if-elif-else statements

  In these conditional statements If statements contain more than one conditional expression and more than one block of code in their body. The else block contains the else block code in its body. Then if the if-block condition satisfies then the if-block's code is executed otherwise it checks for all the elif-block's conditions if any elif block satisfies the condition its block's code is executed otherwise else block's code is executed.

  Syntax

  
  if test expression:
      #Body of if
  elif test expression:
      #Body of elif
  else:
      #Body of else

  Example

  
  num=int(input("Enter Number: "))
  if num>0:
      print("Number is positive")
  elif num<0:
      print("Number is Negative")
  else:
      print("Number is zero")

  Output

  
  Enter Number: -3
  Number is Negative

• Python Nested if-else statements

  This control statement is similar to the above if-else statements, but the difference is there can be multiple if-else statements inside the if-else statement itself.

  Example

              
  #Program to check greatest between 3 numbers
  num1=2
  num2=3
  num3=4
  
  if num1>num2:
      if num2>num3:
          print("num1 is greatest")
      else:
          if num1>num3:
              print("num1 is greatest")
          else:
              print("num3 is greatest")
  elif num2>num3:
      print("num2 is greatest")
  else:
      print("num3 is greatest")

  Output

  num3 is greatest