Why Does `list.append()` Evaluate to False in Python?

Why does list.append evaluate to false in a boolean context?

It might seem counterintuitive that a successful operation like list.append would evaluate to False in a boolean context. The reason lies in Python's principle of command-query separation.

In Python, methods that modify a container in-place typically return None. This follows the idea that a command (such as append) should not return a value, while a query (such as len) should. Exceptions exist for cases where retrieving the value would be computationally expensive or impractical, such as the pop method.

In the case of append, it makes sense for it to return None because it doesn't provide any information about the modified list that isn't already available via other methods. Returning a usable value would introduce unnecessary complexity and potential for confusion.

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