Python not equal operator

Let’s see some examples of not-equal operator in Python 2.7.

$ python2.7
Python 2.7.10 (default, Aug 17 2018, 19:45:58) 
[GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.0.42)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 10 <> 20
True
>>> 10 <> 10
False
>>> 10 != 20
True
>>> 10 != 10
False
>>> '10' != 10
True
>>> 

Here is some examples with Python 3 console.

$ python3.7
Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 26 2018, 23:26:24) 
[Clang 6.0 (clang-600.0.57)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 10 <> 20
  File "<stdin>", line 1
    10 <> 20
        ^
SyntaxError: invalid syntax
>>> 10 != 20
True
>>> 10 != 10
False
>>> '10' != 10
True
>>> 

We can use Python not equal operator with f-strings too if you are using Python 3.6 or higher version.

x = 10
y = 10
z = 20
print(f'x is not equal to y = {x!=y}')
flag = x != z
print(f'x is not equal to z = {flag}')
# python is strongly typed language
s = '10'
print(f'x is not equal to s = {x!=s}')

Output:

x is not equal to y = False
x is not equal to z = True
x is not equal to s = True

When we use not equal operator, it calls __ne__(self, other) function. So we can define our custom implementation for an object and alter the natural output. Let’s say we have Data class with fields - id and record. When we are using the not-equal operator, we just want to compare it for record value. We can achieve this by implementing our own __ne__() function.

class Data:
    id = 0
    record = ''
    def __init__(self, i, s):
        self.id = i
        self.record = s
    def __ne__(self, other):
        # return true if different types
        if type(other) != type(self):
            return True
        if self.record != other.record:
            return True
        else:
            return False
d1 = Data(1, 'Java')
d2 = Data(2, 'Java')
d3 = Data(3, 'Python')
print(d1 != d2)
print(d2 != d3)

Output:

False
True

Notice that d1 and d2 record values are same but “id” is different. If we remove __ne__() function, then the output will be like this:

True
True

You can checkout complete python script and more Python examples from our GitHub Repository.