Python OR Operator

The 'or' operator is a logical operator in Python used to combine two or more conditions. This operation returns a Boolean Value - True if at least one condition is true, and False in case of all conditions are false.

We commonly use Python 'or' operator in if statements, assert statements, while loops, and in expressions where the first truthy value has to be selected from multiple variables.

Flowchart of OR Operation

We will now look at the following flowchart that visually represents the working of the 'or' operator in Python.

Step-by-Step Explanation of the Flowchart:

Step 1: Evaluate the expression X or Y (overall logical condition)

Step 2: Check the value of X (first operand)

• If X == True, the expression X or Y immediately returns True and Y would not be evaluated.
• If X == False, Python checks for second operand Y.

Step 3: Check the value of Y (second operand)

• If Y == True, the result is True.
• If Y == False, the result is False.

Truth Table of Python OR Operator

Using Python OR Operator with Boolean Expressions

Python 'or' operator is generally utilized in order to combine Boolean expressions (conditions that evaluates to either True or False). When we use the 'or' operator, the entire expression returns True if at least one of the conditions is True. It returns False if all conditions are False.

Let us take a simple example showing the use of Python 'or' operator with Boolean expressions.

Output:

 Boolean Expression 1: False Boolean Expression 2: True Result: True 

Explanation:

In the above example, we are given two Boolean expressions as bool_exp_1 and bool_exp_2. We then used the 'or' operator to combine these two expressions. Since one of the expressions is True, the resultant of this operation is also True.

Using Python OR Operator in if

We can use the 'or' operator in the if statement to check multiple conditions. In case, any of the conditions is True, the entire expression evaluates to True.

Let us see an example.

Output:

 The number is either 10 or 20. The number is not 10 or 20. The number is either 10 or 20. 

Explanation:

In this example, we have defined a function as check_number() that takes an argument as num. Inside this function, we have used the 'or' operator in the if statement to check if the passed argument is either 10 or 20. We have then called the check_number() to check different numbers such as 10, 14, and 20.

As a result, if any of the conditions specified in the if statement is True, the print() function inside the if block is execute; otherwise the else block is executed.

Python OR Operator - Short Circuiting

In Python, Short-circuiting refers to the stoppage of the execution of Boolean operation if the truth value of the expression has already been determined.

In case of the 'or' operator, if the first operand or Boolean expression is True, Python will not check of the second one, as the entire expression is already True.

We will now take a look at the following example:

Output:

 Inside the 'True' function Case 1: True Inside the 'True' function Case 2: True Inside the 'False' function Inside the 'True' function Case 3: True Inside the 'False' function Inside the 'False' function Case 4: False 

Explanation:

In this example, we defined two functions as true() and false(). Inside these functions, we have returned the Boolean values - True and False. We have then used the 'or' operator to combine these functions during calls.

As a result, we can see how Python short-circuiting when the first operand in True.

Conclusion

In this tutorial, we learned about Python 'or' operator with various examples. We discussed how to use the 'or' operator with Boolean expressions and in the if statements. At last, we discussed, how short circuiting affects to flow of execution in Python 'or' operator.

Python OR Operator FAQs

1. What does the 'or' operator do in Python?

It returns True in case any of the provided operands is true. In short, when there are multiple conditions and any single one is needed to execute the block.

2. What is short-circuiting in or operator?

It allows halting of further checks in case when any True statement is found. Further computation no longer becomes necessary thereby improving efficiency.

3. Can or be used with values that are not Booleans?

Sure! In fact, treated as False are values such as 0, " ", None, and []. While anything else is regarded as True. In case all 3 flag values were false the last is returned. Otherwise the first truthful value is selected.

4. What's the difference between or and |?

The 'or' operator is a logical operator used with Boolean values, while the '|' operator is a bitwise operator used with integers. It compares each bit of its operands and returns a result with bits set where either operand has a 1.

Output:

 True 7 (binary: 101 | 011 = 111) 

5. Can we use or in if statements?

Yes! It's commonly used to check if any one of multiple conditions is True.