Should You Use List Comprehensions for Side Effects in Python?

Should List Comprehensions Be Used for Side Effects in Python?

In Python, functions are often called for their side effects rather than their return values. Such side effects may include printing to the screen, updating a graphical user interface, or writing to a file.

When it comes to invoking functions with side effects using list comprehensions, there are two general approaches:

Approach 1: List Comprehension for Side Effects

[fun_with_side_effects(x) for x in y if (...conditions...)]

Approach 2: Conditional Loop

for x in y:
    if (...conditions...):
        fun_with_side_effects(x)

The question arises: which approach is more Pythonic?

Answer: Approach 2 is Strongly Recommended

Using list comprehensions for side effects is strongly discouraged in Python. The main reason for this is the unnecessary creation of an intermediate list. This list is discarded immediately after it is created, which can be a significant waste of resources if the list is large.

In contrast, the conditional loop approach does not create any unnecessary data structures. It evaluates each element in the input list directly, potentially minimizing overhead.

The above is the detailed content of Should You Use List Comprehensions for Side Effects in Python?. For more information, please follow other related articles on the PHP Chinese website!