Gerhard Häring wrote:
Martin v. Löwis wrote:
Are they widespread? I haven't noticed, yet.
I prefer to write it explicitly:
if len(lst) > 0:
I prefer to test explicitly for the truth value of the
list. I don't want to test whether the length of the list
is greater than 0 (in fact, I don't care about the length
property of the list at all) - I want to know whether the
list is empty (or not empty). The Python syntax for this
test is
if lst:
# not empty
or
if not list:
#empty
[...]
You're right - as most of the time ;-) This makes a lot of sense to me.
The reason I preferred len(), btw., was only that len() make it clear
that the argument is a sequence.
Maybe I was just too annoyed by lots of Python code I read that looked
like this:
def foo(x, y, z):
if x:
...
else:
...
with poorly named variables where I didn't know what the heck the
variables are (bool, list, instance, ...). I hate it when I have to look
for the actual method calls to figure out what's going in. Better
variable naming and small comments would often help.
In my view, that is only excusable in throw-away private code or in
languages like early BASIC where only one letter is allowed, and even
then, 'x' should be a number, not a collection.
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