Which equivalent operator is different in Python?

As with most languages, the difference operator in Python is != . It is worth remembering that it compares only the value between the operands and not their identities.

a = 2
b = 3

if a != b:
    print('a é diferente de b')
else:
    print('a é igual a b')

By now, the != operator implicitly invokes the __ne__ method of the first operand, passing the second as a parameter, so if you need to override that operator in a class, you can do:

class Foo:
    def __init__(self, value):
        self.value = value

    def __ne__(self, other):
        return self.value != other.value

f1 = Foo(1)
f2 = Foo(1)

print(f1 != f2)  # False

Without overloading the method, the result would be True , indicating that the objects are different, even though they appear to be the same.

The is (or is not ) operator checks the identity of objects, not just their values. This is evident, for now, when working with changeable types:

a = [1]
b = [1]

print(a != b)  # False
print(a is not b)  # True

The lists a and b have the same value but are not the same object.

Additional readings

• In Python, what are the consequences of using 'is' instead of '=='
• In Python, what's the difference between == and the is?

Other operators in the language are:

• Addition, a + b , when a and b are numeric;

  >>> 1 + 2
  3
  

• Concatenation, a + b , when a and b are sequences;

  >>> 'Anderson' + ' ' + 'Woss'
  'Anderson Woss'
  >>> [1, 2] + [3, 4]
  [1, 2, 3, 4]
  

• Contention, a in b ;

  >>> 1 in [1, 2, 3, 4]
  True
  

• True division, a / b , which returns the actual result;

  >>> 5/2
  2.5
  

• Division with truncation, a // b , which returns only the integer part;

  >>> 5//2
  2
  

• And binary, a & b ;

  >>> 1 & 3
  1
  

• Exclusive binary OR, a ^ b ;

  >>> 1 ^ 2
  3
  

• Binary inversion, ~a ;

  >>> ~2
  -3
  

• OR binary, a | b ;

  >>> 1 | 2
  3
  

• Exponentiation, a**b ;

  >>> 2**10
  1024
  

• Identity, a is b ;

  >>> 1 is None
  False
  

• Identity, a is not b ;

  >>> 1 is not None
  True
  

• Indexing, obj[k] ;

  >>> obj = [1, 2, 3]
  >>> obj[1]
  2
  

• Index assignment, obj[k] = v ;

  >>> obj = [1, 2, 3]
  >>> obj[2] = 4
  >>> obj
  [1, 2, 4]
  

• Deletion by index, del obj[k] ;

  >>> obj = [1, 2, 3]
  >>> del obj[1]
  >>> obj
  [1, 3]
  

• Binary shift to left, a << b ;

  >>> 4 << 1
  8
  

• Binary shift to right, a >> b ;

  >>> 4 >> 1
  2
  

• Rest of division, a % b ;

  >>> 5 % 2
  1
  

• Multiplication, a * b ;

  >>> 2 * 3
  6
  

• Matrix multiplication, a @ b ( versions 3.5+ );

  See PEP 465 ;

• Arithmetic negation, -a ;

  >>> -4
  -4
  

• Logical negation, not a ;

  >>> not True
  False
  

• Positive, +a ;

  >>> +4
  4
  

• Slice, seq[i:j] ;

  >>> obj = [1, 2, 3, 4, 5]
  >>> obj[1:3]
  [2, 3]
  

• Assignment by slicing, seq[i:j] = values ;

  >>> obj = [1, 2, 3, 4, 5]
  >>> obj[1:3] = [8, 9]
  >>> obj
  [1, 8, 9, 4, 5]
  

• Deletion by slicing, del seq[i:j] ;

  >>> obj = [1, 2, 3, 4, 5]
  >>> del obj[1:3]
  >>> obj
  [1, 4, 5]
  

• Formatting string , s % obj (prefer method format or f-strings );

  >>> 'Olá, %s' % 'mundo'
  'Olá, mundo'
  

• Subtraction, a - b ;

  >>> 3 - 1
  2
  

• Truth test, if obj: ... ;

  >>> obj = 3
  >>> if obj: print('Ok')
  'Ok'
  

• Less than, a < b ;

  >>> 1 < 2
  True
  

• Less than or equal to, a <= b ;

  >>> 1 <= 2
  True
  

• Greater than, a > b ;

  >>> 1 > 2
  False
  

• Greater than or equal to, a >= b ;

  >>> 1 >= 2
  False
  

• Enter, not inclusive, a < v < b ;

  >>> v = 5
  >>> 1 < v < 9
  True
  

• Enter, inclusive, a <= v <= b ;

  >>> v = 5
  >>> 1 <= v <= 9
  True
  

• Equality, a == b ;

  >>> 1 == 2
  False
  

• Difference, a != b ;

  >>> 1 != 2
  True
  

• Difference, a <> b (obsolete from version 2.5, removed in 3+ versions);

  >>> 1 <> 2
  True
  

Further information can be found at official documentation .

In Python you could use different "!=", or not "is not"

if "Foo" != "Bar":
    return "Diferente"

if "Foo" is not "Bar":
    return "Diferente"