Python Conditions and If statements

 

Python Conditions and If statements

Python supports the usual logical conditions from mathematics:

• 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

These conditions can be used in several ways, most commonly in "if statements" and loops.

An "if statement" is written by using the if keyword.

Example :

a = 33

b = 200

if b > a:

  print("b is greater than a")

OUTPUT:

b is greater than a

Elif

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

example:

a = 33
b = 33
if b > a:
  print("b is greater than a")
elif a == b:
  print("a and b are equal")

output:

a and b are equal

In this example a is equal to b, so the first condition is not true, but the elif condition is true, so we print to screen that "a and b are equal".

Else

The else keyword catches anything which isn't caught by the preceding conditions.

Example

a = 200

b = 33

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 is greater than b

In this example a is greater than b, so the first condition is not true, also the elif condition is not true, so we go to the else condition and print to screen that "a is greater than b".

You can also have an else without the elif:

EXAMPLE:

a = 200
b = 33
if b > a:
  print("b is greater than a")
else:
  print("b is not greater than a")

OUTPUT:

b is not greater than a