Python Conditions

Python If ... Else:

Python contains three keywords for checking conditions.

• if
• else
• elif

Logical conditions are used with if statements these conditions are:

• Equals: a == b
• Not Equals: a != b
• Less than: a < b
• Less than or equal to: a <= b
• Greater than: a > b
• Greater than or equal to: a >= b

1. if 

Example:

a = 30

b = 30
if b == a:
  print("b is equal to a")

Output:

b is equal to a

Note that we have to give indentation after if statement which tell that the print statement is under if block otherwise it will be error.        

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2.else

The else keyword get executed if the preceding conditions is false.

Example:

a = 90
b = 33
if b > a:
  print("b is greater than a")

else:
  print("a is greater than b")

Output:

a is greater than b

Here the else statement get executed.

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3. elif

The elif keyword is a way of saying that "if the previous conditions were not true, then try this condition".

Example:

a = 90
b = 90
if b > a:
  print("b is greater than a")
elif a == b:
  print("a and b are equal")
else:
  print("a is greater than b")

Output:

a and b are equal

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 4. Nested if:

It is a ladder of if statement or we can say multiple if statement.
It is written as:

Example:

a = 90
b = 90
if b > a:
  print("b is greater than a")
elif a == b:
  print("a and b are equal")
elif a > b:

  print("a is greater than b")

Output:

a and b are equal

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5. Short hand if:

Example:

a = 90

b = 90

if a = b: print("a is equal to b")

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6. Short hand if-else:

Example:

print("A") if a < b else print("B")

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7. if-else using (and) and (or):

Example 1:

if a > b and c > a:
  print("Both conditions are True")

Here the print block will execute only when a>b and c>a are true.

Example 2:

if a > b or a > c:
  print("At least one of the conditions is True")

Here the print block will execute only when one of the condition is true.