On 10/10/2013 9:33 AM, Ethan Furman wrote:
On 10/10/2013 12:43 AM, Terry Reedy wrote:
On 10/10/2013 2:45 AM, Chris Angelico wrote:
first_element = some_list[0] # Oops, may crash
some_list[0:1] always works, and sometimes is usable, but you still
cannot index the slice.
Not if some_list is None, False, or another non-indexable type.
Did you really not understand that some_list is intended to be a list?
Just like my_string, for instance, would be a string? Chris's statement
further specifies some_list as a list that is expected to not be empty,
but might be -- so one has to guard against the possibility.
The trick of slicing instead of indexing in this context is not obvious
to everyone learning Python. Most other languages only have indexing. I
learned the trick years ago when someone posted it on this list.
--
Terry Jan Reedy
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