Need help understanding list structure
Erik
python at lucidity.plus.com
Mon May 2 17:48:33 EDT 2016
On 02/05/16 22:30, moa47401 at gmail.com wrote:
> Can someone help me understand why or under what circumstances a list
> shows pointers instead of the text data?
When Python's "print" statement/function is invoked, it will print the
textual representation of the object according to its class's __str__ or
__repr__ method. That is, the print function prints out whatever text
the class says it should.
For classes which don't implement a __str__ or __repr__ method, then
the text "<CLASS object at ADDRESS>" is used - where CLASS is the class
name and ADDRESS is the "memory pointer".
> If I iterate over the list, I do get the actual text of each element
> and am able to use it.
>
> Also, if I iterate over the list and place each element in a new list
> using append, then each element in the new list is the text I expect
> not memory pointers.
Look at the __iter__ method of the class of the object you are iterating
over. I suspect that it returns string objects, not the objects that are
in the list itself.
String objects have a __str__ or __repr__ method that represents them as
the text, so that is what 'print' will output.
Hope that helps, E.
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