When the comparison does not make sense, an Exception is caused. Python's not operator returns True when placed before something that's false. x is not y, here is not results in 1 if id(x) is not equal to id(y). Check if a string is empty using not. ‘If’ statement in Python is an eminent conditional loop statement that can be described as an entry level conditional loop, where the condition is defined initially before executing the portion of the code. Python Program #Python's not to see if things didn't happen. The “if statement” in Python does this specifically by testing whether a statement is true, and then executing a code block only if it is. Here is another example: Pay with Overtime. We can use Python not equal operator with f-strings too if you are using Python 3.6 or higher version. a = 3 b = 2 if a==5 and b>0: print('a is 5 and',b,'is greater than zero.') Python is dynamically, but strongly typed, and other statically typed languages would complain about comparing different types. In the following example, we will use and operator to combine two basic conditional expressions in boolean expression of Python If-Else statement.. Python Program. To make an if statement test if something didn't happen, we put not in front of our condition. Example 2: Python If-Else Statement with AND Operator. If not found, it returns -1. In this step, we will see what happens when if condition in Python does not meet. Python Operators Precedence The following table lists all operators from highest precedence to lowest. So, to check if a string is empty or not we can just apply “not” operator with it i.e. Python supports the usual logical conditions from mathematics: Equals: a == b Not Equals: a != b Less than: a < b Less than or equal to: a <= b Greater than: a > b Greater than or equal to: a >= b These conditions can be used in several ways, most commonly in … This will always return True and “1” == 1 will always return False since the types differ. Now the expression: number not in range() returns True if the number is not present in the range, and False if number is present in the range. And when before something that's true, we get False (Python Docs, n.d.).. That's how we test if it's True that something didn't happen. else: print('a is not 5 or',b,'is not greater than zero.') Python Conditions and If statements. Code Line 5: We define two variables x, y = 8, 4; Code Line 7: The if Statement in Python checks for condition x