Python Ternary Operator

Python is widely recognized for its readability and simplicity, which often resembles the human language. One of its most significant features is its ability to define, implement, and perform tasks using fewer lines of code. However, when conditional logic is introduced, the code can sometimes become difficult to follow. Ternary operators offer a solution to this issue by allowing conditional statements to be written in a more concise and readable manner. In this blog, you will explore ternary operators in Python through clear explanations and examples.

Table of Contents:

• What are Ternary Operators in Python?
• Basic Syntax of Ternary Operator in Python
• Different Ways to Use Ternary Operators in Python
  • Ternary Operators With Tuples in Python
  • Ternary Operators With Dictionaries in Python
• Using Lambda Function with Ternary Operators in Python
• Common Mistakes to Avoid When Using Ternary Operators in Python
• Difference Between Ternary Operator and If-Else Statement
• Conclusion

What are Ternary Operators in Python?

The Ternary Operator is a Python Operator that is useful for enhancing the readability of the code. It is a shorthand way of writing the if-else statements. Instead of using an if-else block, we can implement it in a single line using the Ternary operator. This keeps your code simple and clean.

Ternary Operators are also called conditional expressions in Python.

Basic Syntax of Ternary Operator in Python

The ternary operator expression returns a value in Python. The syntax is explained below.

variable = value_if_true if condition else value_if_false

• value_if_true is the value that gets returned if the condition is true.
• condition holds the expression that is checked.
• value_if_false is the value that gets returned if the condition is false.

Note: The ternary operator gives a value, so you should store it in a variable or use it right away. If not, the value will be ignored.

Example:

Output:

Explanation: Since the condition 3<4 was true, “Yes” got printed.

Different Ways to Use Ternary Operators in Python

The syntax of the ternary operator can be adapted differently depending on the use cases. They can be implemented in patterns of tuples and dictionaries. Let us look at them one by one.

Ternary Operators With Tuples in Python

The idea here is to store both value_if_false and value_if_true in a tuple and select one based on the boolean condition. Since False is treated as 0 and True as 1, we place value_if_false at index 0 and value_if_true at index 1. This allows the boolean result to act as an index to directly pick the correct value.

Syntax:

result = (value_if_false, value_if_true)[condition]

Example:

Output:

Explanation: Here, 10 < 20. Therefore, a < b is True, which equals 1, and tuple[1] is accessed, returning b (i.e., 20).

Caution:

This method evaluates both the values b and a before even checking the condition. This can be inefficient or even problematic if one of the values is computationally expensive or causes side effects (like a function call or error). Use this way of the ternary operator only if you are certain that both expressions are safe and inexpensive.

Boost your tech career with Python – Sign up now!

Practical projects, job-ready skills, and expert guidance.

Explore Program

Ternary Operators With Dictionaries in Python

Another technique is using dictionaries. Here, we set the keys as True and False and assign them their corresponding values. Whatever result is given by the dictionary, that key is chosen, and that value is returned.

Syntax:

result = {True: result_if_true, False: result_if_false}[condition]

Example:

Output:

Explanation: In this example, the condition returns False. Therefore, the key-value pair that was chosen was {‘False’:b}. Hence, b, which is 20, was printed.

Caution:

Just like with tuples, both values are evaluated when the dictionary is created. Only use this method when the values are computationally inexpensive.

Using Lambda Function with Ternary Operators in Python

When the conditions and values are computationally inexpensive, it is recommended to use ternary operators in Lambda Functions. This is called inline decision logic.

Example:

Output:

Explanation: In the case of ‘x=3,’ since x>0, ‘Positive’ was printed. Similarly, for ‘x=-1’, ‘Negative or Zero’ was printed.

Common Mistakes to Avoid When Using Ternary Operators in Python

1. While writing code in one line looks neat, the readability suffers when the conditions are too long or too complex. This also makes it difficult for beginners or even developers to read your code.

Example:

The above example is quite hard to read and follow through. Using the ternary operator here does not improve the code. It is better to use the normal if-elif-else block here.

Ternary operators are designed to return a single value based on a condition. They are not meant for executing multiple lines of code or performing actions like printing or calling functions.

Example:

Explanation: Even though this works, it is hard to read and goes against the purpose of a ternary operator. You are using it to perform two actions (print statements), which is better handled using a normal if-else block.

Correct Usage:

Output:

Explanation: Here, we select the value between “Passed” and “Failed” and assign it to the result instead of performing two actions.

2. In the tuple and dictionary patterns, both the values are evaluated even before the condition is checked. If the values contain a function, it will get called regardless of what the conditional expression returns. This leads to unnecessary work or even errors.

Example:

Output:

Explanation: Normally, since the condition is True, “Safe” should get printed. But as we discussed, both values are evaluated. Hence, risky() was called, and the exception was printed. 

Difference Between Ternary Operator and If-Else Statement

In the table given below, you will find the major differences between the ternary operators and the if-else statement at a glance.

Conclusion

Ternary operators in Python offer a concise and elegant way to write conditional expressions. They can make your code shorter and easier to understand when used wisely. For simple decisions, ternary operators are a great tool. However, for complex conditions, it’s better to stick with traditional if-else statements to maintain clarity and readability.

To take your skills to the next level, check out this Python training course and gain hands-on experience. Also, prepare for job interviews with Python interview questions designed by industry experts.

Python Ternary Operators – FAQs