Python Greater Than

The Python greater than (left>right) operator returns True when its left operand exceeds its right operand. When the left operand is smaller than or equal to the right operand, the > operator returns False. For example, 3>2 evaluates to True, but 2>3 and 3>3 both evaluate to False.

Examples

Let’s explore a couple of examples regarding the greater than operator.

Is 3 greater than 2 and 2?

>>> 3 > 2
True

What about 2 greater than 3?

>>> 2 > 3
False

Can you compare collections such as lists?

>>> [1, 2] > [99]
False
>>> [1, 2] > [0]
True
>>> [1, 2] > [1, 2, 3]
False
>>> [1, 2] > [1, 1, 3]
True

Yes!

The list “greater than” operator iterates over the lists and checks pairwise if the i-th element of the left operand is greater than the i-th element of the right operand. You can find a detailed discussion on the greater than operator with list operands below in this article.

Can you use the greater than operator on custom objects? Yes!

Python Greater Than on Custom Objects

To use the “greater than” operator on custom objects, you need to define the __gt__() dunder method that takes two arguments: self and other. You can then use attributes of the custom objects to determine if one is greater than the other.

In the following code, you check if a Person is greater than the other Person by using the age attribute as a decision criterion:

class Person:
    def __init__(self, age):
        self.age = age

    def __gt__(self, other):
        return self.age > other.age



alice = Person(10)
bob = Person(12)

print(alice > bob)
# False

print(bob > alice)
# True

Because Alice is 10 years old and Bob is 12 years old, the result of alice > bob is False and bob > alice is True.

Python Greater Than If Statement

The Python greater than > operator can be used in an if statement as an expression to determine whether to execute the if branch or not. For example, the greater than if condition x>3 checks if the value of variable x is greater than 3, and if it is, the if branch is entered.

The following code asks the user to input their age using the input() function. It then checks if the user input, when converted to an integer using int(), is larger than 18. If so, it enters the if branch. If not, it enters the else branch.

x = int(input('your age: '))

if x > 18:
    print('you can vote')
else:
    print('you cannot vote - sorry')

Here’s an example execution of this code where the if branch is not entered:

your age: 18
you cannot vote - sorry

Here’s an example execution where the if branch is entered:

your age: 21
you can vote

Python Greater Than But Less Than

Python has a “greater than but less than” operator by chaining together two “greater than” operators. For example, the expression 5 < x < 18 would check whether variable x is greater than 5 but less than 18. Formally, the expression x < y < z is just a shorthand expression for (x < y) and (y < z).

Here’s a minimal example that checks if variable x is greater than 2 but less than 18:

x = 8

# Is x greater than 2 but less than 18?
if 2 < x < 18:
    print('yes')

# Output: yes

The code enters the if branch because the if condition is fulfilled.

Python Greater Than Lists

The list “greater than” operator iterates over the lists and checks pairwise if the i-th element of the left operand is greater than the i-th element of the right operand.

>>> [1, 2] > [99]
False
>>> [1, 2] > [0]
True
>>> [1, 2] > [1, 2, 3]
False
>>> [1, 2] > [1, 1, 3]
True

• [1, 2] > [99]. Python first checks 1 > 99 which is False, so it immediately returns False.
• [1, 2] > [0]. Python first checks 1 > 0 which is True.
• [1, 2] > [1, 2, 3]. Python first compares 1 and 1—a tie! So, it moves on to the second elements 2 and 2—tie again! So, it moves to the third elements as a tie-breaker. But only the second list has a third element so it is considered greater than the first and the result of the operation is False.
• [1, 2] > [1, 1, 3]. Python compares elements 1 and 1—a tie! But then it compares the second elements 2 and 1 and determines that the first is greater than the second, so the result is True.

The same method also applies to strings and other sequence types in Python such as tuples.

Is Everything Greater Than None?

You cannot use the greater than operator with None as one of its operands. Python 3 expects that both operands implement the comparable interface, but the None type does not. That’s why Python raises a TypeError if you try to compare variables with None.

>>> 21 > None
Traceback (most recent call last):
  File "<pyshell#0>", line 1, in <module>
    21 > None
TypeError: '>' not supported between instances of 'int' and 'NoneType'

Comparison Operators

Comparison operators are applied to comparable objects and they return a Boolean value (True or False).