Generator question

[Robert Kern]

Timothy Wu wrote:
> Hi,
> 
> Using generator recursively is not doing what I expect:
> 
> def test_gen(x):
>     yield x
>     x = x - 1
>     if x != 0:
>         test_gen(x)

The only thing that the last line does is *create* a new generator object. You
need to actually iterate over it and yield its values. E.g.


In [2]: def test_gen(x):
   ...:     yield x
   ...:     x -= 1
   ...:     if x != 0:
   ...:         for y in test_gen(x):
   ...:             yield y
   ...:
   ...:

In [3]: list(test_gen(3))
Out[3]: [3, 2, 1]


-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco