Note that comparing equality of lists and tuples will assume that identity of objects are equal (because this is a fast check). An exceptionĪ notable exception is nan - it always tests as not equal to itself: > nan = float('nan')Ĭhecking for identity can be much a much quicker check than checking for equality (which might require recursively checking members).īut it cannot be substituted for equality where you may find more than one object as equivalent. Since tests for equality can be customized, this inference does not always hold true for all types. The contrapositive is also usually true - if somethings test as not equal, you can usually infer that they are not the same object.

The operators, =, >=, > class Object(object): pass =: check for equality - the semantics are that equivalent objects (that aren't necessarily the same object) will test as equal. Yes, they have a very important difference. Is there a difference between = and is in Python? This is another obvious reason not to use is: the behavior is left up to implementations when you're erroneously using it for value equality. Here's an example demonstrating this: > for i in range(250, 260): a = i print '%i: %s' % (i, a is int(str(i))) What's going on here? It turns out the reference implementation of Python caches integer objects in the range -5.256 as singleton instances for performance reasons. This is inconsistent with the earlier result. That's pretty much what we expected: a and b have the same value, but are distinct entities. Something else to note: because of the way the CPython reference implementation works, you'll get unexpected and inconsistent results if you mistakenly use is to compare for reference equality on integers: > a = 500 For example, the intention of your example is probably to check whether x has a value equal to 2 ( =), not whether x is literally referring to the same object as 2. In general, when you are comparing something to a simple type, you are usually checking for value equality, so you should use =.

Use it when you would like to know if two references refer to the same object. Use it when you would like to know if two objects have the same value. This loop exists when the condition becomes false.There is a simple rule of thumb to tell you when to use = or is. 5 Variable value starts with the initial value 5, and decrement the value by 1 for every iteration. In the below example, we will iterate the loop until the condition value != 0. While working with the while loop we have to use the expression when to exists the loop, and the expression could be with != operator sometimes. The number of characters in the string “Python” is 6, which is not equal to 5. Let’s look at another example in which we will compare the string length. So the condition inside the if statement will become True and the statement inside the if statement is executed. Here, As ravi's age is not equal to 20, != return True. In Python 2 the operator used for Not Equal is “”, and this is deprecated in Python 3. From Python-3, we need to use this != operator. If they are not equal, False is returned, otherwise True is returned. Like any other programming language Python Not Equal (!=) operator is used to checking the provided values/expressions are False or not. # Use while loop to display the string till the value becomes 0. # Example 5: Not Equal operator in While loop # Example 4: Not Equal operator in Compound statements # Example 3: Not Equal operator in if statement # Example 2: Not Equal operator with strings # Example 1: Not Equal operator with integer variables For a better understanding of each example, please go through the entire article. If you are already working on Python, you can quickly look into it. Let’s quickly see the examples below to understand using the Not Equal operator in different scenarios. Quick Examples of using Not Equal Operator

Python not equal