Python Ternary List Comprehension

Let’s investigate Python ternary list comprehension with some code examples. 🔥🔥

The ternary operator in Python is a concise way to execute an “if-else” condition within a single line or expression. It allows for conditional assignment of values. The basic syntax of the ternary operator is:

value_if_true if condition else value_if_false

Here’s how it works:

• condition: This is the boolean expression that the ternary operator evaluates.
• value_if_true: The value to be assigned if the condition is True.
• value_if_false: The value to be assigned if the condition is False.

This operator is particularly useful for short and readable conditional assignments. Here’s a simple example:

x = 5
result = "Greater than 10" if x > 10 else "Less than or equal to 10"
print(result)

#Output
#Less than or equal to 10

In this example, result will be “Less than or equal to 10” because the condition x > 10 is False. If x were greater than 10, result would be “Greater than 10”.

The Python ternary operator in list comprehensions is an efficient way to evaluate conditions within the same. Here are two simple examples:

print(["even" if x % 2 == 0 else "odd" for x in range(1, 6)])

#output
#['odd', 'even', 'odd', 'even', 'odd']

For the first one, all we’re doing is creating a list of “even” or “odd” based on the parity of numbers in a range. This list comprehension iterates through numbers from 1 to 5. For each number x, it checks if x is divisible by 2 (x % 2 == 0). If it is divisible, “even” is added to the list; otherwise, “odd” is added. The result is a list that labels each number as either “even” or “odd”.

Here’s another example:

print(["positive" if x > 0 else "negative" for x in [-2, -1, 0, 1, 2]])

#output
#['negative', 'negative', 'negative', 'positive', 'positive']

Here, we’re creating a list of “positive” or “negative” based on the sign of numbers in an existing list. This list comprehension iterates through a predefined list of numbers: [-2, -1, 0, 1, 2]. For each number x in this list, it checks if x is greater than 0. If x is greater than 0, “positive” is added to the new list; if x is less than or equal to 0, “negative” is added. The result is a list indicating whether each number is “positive” or “negative”.

Finally, let’s do more complex examples of a Python Ternary In a List Comprehension:

print(["small" if x < 5 else ("medium" if x < 10 else "large") for x in range(1, 15)])

#output
#['small', 'small', 'small', 'small', 'medium', 'medium', 
#'medium', 'medium', 'medium', 'large', 'large', 'large', 'large', 'large']

Here, we are using a nested ternary operator for categorizing numbers. For each number x in the range from 1 to 14, it categorizes x as “small” if it’s less than 5, “medium” if it’s between 5 and 9, and “large” if it’s 10 or greater. The result is a list that classifies each number into one of these three categories.

Here’s another complex example:

print([sublist[:2] if len(sublist) > 3 else sublist for sublist in [[1, 2, 3], [4, 5, 6, 7], [8, 9]]])

#Output
#[[1, 2, 3], [4, 5], [8, 9]]

This list comprehension operates on a list of lists. For each sublist in the outer list, it checks if the length of the sublist is greater than 3. If it is, only the first two elements of the sublist are included in the new list (sublist[:2]). If the sublist has 3 elements or fewer, the entire sublist is included. The resulting list is a mix of full and truncated sublists, depending on their initial sizes.

So there you have it! You learned how to use Python Ternary In List Comprehension. Happy coding! 🔥🔥🔥