Does Not Equal in Python: The != Operator Explained

Does not equal in Python is written as !=. It compares two values and returns True when they’re different and False when they’re the same:

5 != 3          # True
"NY" != "NY"    # False

For this one I used Python 3.12.5 on a Windows laptop, and the screenshots show the scripts running in Command Prompt.

I’ll cover how != treats numbers and strings, when to use is not instead, the float and NaN traps, loops, and custom classes.

How the not equal operator works in Python

!= works on any two values. It checks value, not type, so 1 != 1.0 is False, while 1 != "1" is True because a number never equals text:

print(5 != 3)              # True
print(5 != 5)              # False
print("Boston" != "boston")  # True: strings are case-sensitive
print(1 != "1")            # True: an int never equals a str
print(1 != 1.0)            # False: 1 and 1.0 are equal
print([1, 2] != [1, 2])    # False: same contents

state = "NY"
if state != "OR":
    print("Sales tax applies in", state, "(Oregon has none)")

Output:

True
False
True
True
False
False
Sales tax applies in NY (Oregon has none)

Need to ignore case? Compare a.lower() != b.lower(). Case-insensitive string comparisons covers casefold() too.

What’s the difference between != and is not?

!= asks whether two values differ. is not asks whether they’re different objects in memory. Two lists with the same items are equal, but they’re still separate objects:

a = [10, 20]
b = [10, 20]
c = a

print(a != b, a is not b)   # equal values, different objects
print(a != c, a is not c)   # the very same object

result = None
print(result is not None)   # the right way to test for None
print(result != None)       # works, but style guides say use is not

Output:

False True
False False
False
False

PEP 8 says to compare with None using is or is not, never == or !=. There’s more in is None vs == None in Python.

Why does 0.1 + 0.2 != 0.3 return True?

Floats are stored in binary, so 0.1 + 0.2 is really 0.30000000000000004. Testing floats with != gives surprising answers; math.isclose() is the safe check:

import math

total = 0.1 + 0.2
print(total)
print(total != 0.3)                       # True, surprisingly
print(not math.isclose(total, 0.3))       # False: close enough

nan = float("nan")
print(nan != nan)                         # True: NaN never equals anything
print(math.isnan(nan))

Output:

0.30000000000000004
True
False
True
True

NaN is the other odd one: it’s not equal to anything, even itself. Use math.isnan() to spot it rather than x != x, which works but confuses readers.

Using does not equal in while loops and filters

!= is a natural stop condition: keep going while the value isn’t the one you want. It’s also a quick filter in a comprehension:

answers = iter(["maybe", "no", "yes"])

reply = ""
while reply != "yes":
    reply = next(answers)
    print("Got:", reply)

prices = [19.99, 0, 4.50, 0, 12.00]
print([p for p in prices if p != 0])

Output:

Got: maybe
Got: no
Got: yes
[19.99, 4.5, 12.0]

For the loop side of this, see the Python while loop guide. And if else in Python shows != in conditions.

Not equal with custom classes (and the old <> operator)

When you define __eq__, Python builds != from it automatically by inverting the result. You only write __ne__ if you need something unusual:

class Product:
    def __init__(self, sku, price):
        self.sku, self.price = sku, price

    def __eq__(self, other):
        return isinstance(other, Product) and self.sku == other.sku

shirt_a = Product("TS-100", 24.99)
shirt_b = Product("TS-100", 19.99)     # same SKU, sale price
mug = Product("MG-200", 12.50)

print(shirt_a != shirt_b)   # False: __ne__ inverts __eq__ for you
print(shirt_a != mug)       # True

try:
    compile("5 <> 3", "old.py", "eval")
except SyntaxError as err:
    print("SyntaxError:", err.msg, "(<> was removed in Python 3)")

Output:

False
True
SyntaxError: invalid syntax (<> was removed in Python 3)

If you’re porting old Python 2 code, replace every <> with !=. Python 3 doesn’t accept it at all.

Comparison operators in Python

Operator	Meaning	Example	Result
==	Equal	5 == 5	True
!=	Not equal	5 != 3	True
is not	Not the same object	x is not None	True if x has a value
not in	Not a member	"TX" not in states	True if missing
<, >	Less, greater	3 < 5	True

Comparisons pair naturally with these guides:

• What does in mean in Python
• Check if a variable is None
• Increment and decrement operators
• Break and continue in Python

Frequently asked questions