2018-03-06 17:55 GMT+03:00 Chris Angelico <ros...@gmail.com>: > If the first argument is None, the identity function is assumed. That > is, all elements of the iterable that are false are removed; it is > equivalent to (item for item in iterable if item). It is approximately > equivalent to (but faster than) filter(bool, iterable). > > ChrisA > -- > https://mail.python.org/mailman/listinfo/python-list >
If you look in C source for `filter_next` https://github.com/python/cpython/blob/5d92647102fac9e116b98ab8bbc632eeed501c34/Python/bltinmodule.c#L593, there is a line: int checktrue = lz->func == Py_None || lz->func == (PyObject *)&PyBool_Type; So the only difference between `filter(None, ls`) and `filter(bool, ls)` is LOAD_NAME vs LOAD_CONST and that `None` is checked before than `bool`. With kind regards, -gdg -- https://mail.python.org/mailman/listinfo/python-list
