On Tue, Nov 24, 2020 at 7:00 AM Ethan Furman <[email protected]> wrote:
On 11/23/20 11:06 AM, Larry Hastings wrote:
> On 11/23/20 8:15 AM, Brian Coleman wrote:
>> def process(root_node: Node):
>> def process_node(node: Node):
>> if isinstance(node, StringNode):
>> return node.value
>> elif isinstance(node, NumberNode):
>> return float(node.value)
>> elif isinstance(node, ListNode):
>> return [process_node(child_node) for child_node in
node.children]
>> elif isinstance(node, DictNode):
>> return {key: process_node(child_node) for key, child_node in
node.children}
>> else:
>> raise Exception('Unexpected node')
>
> You don't need the "else".
Without the "else" errors will pass silently.
> And you can change all your "elif"s into "if"s too.
On average, doubling your comparisons and therefore becoming slower.
I think the implication is that, since all the successful if
statements go into returns, you can leave off the "else" and just put
the "raise" immediately. It's a special case that applies ONLY to
situations where the pattern matching is the entire purpose of the
function.