yield all entries of an iterable

[Stefan Schwarzer]

Hi Cameron,

On 2010-10-25 01:08, Cameron Simpson wrote:
> On 24Oct2010 20:58, Stefan Schwarzer <sschwarzer at sschwarzer.net> wrote:
> | On 2010-10-21 00:27, Sebastian wrote:
> | > Is there a simpler way to yield all elements of a sequence than this?
> | > for x in xs:
> | >     yield x
> | 
> | Can you give an example where you would need this? Can't
> | you just iterate over the sequence?
> 
> The usual example is when the sequence comes from inside.
> Example, closely resembling some code from on of my projects:
> 
>   def leaves(N):
>     if N.isleaf:
>       yield N
>     for subN in N.subnodes:
>       for leaf in leaves(subN):
>         yield leaf
> 
> which walks a tree structure returning leaf nodes.
> 
> The point is that you're calling leaves() on the subnode and yiled them
> directly to the outside. The caller may not even know there are "subnodes".

>From the question and the code snippet the OP gave I assumed
he meant that there already was a sequence (i. e. linear
structure) to begin with.

By the way, I think a well-known example of what you
describe is `os.walk`.

Stefan