1 | initial version |
sage: Bob="xyz"
sage: sB = subsets(Bob)
sage: sB
<generator object powerset at 0x18fe82f00>
At this point, sB
is a generator, and after you've done map(str,sB)
, the generator has been exhausted, so doing map(str,sB)
a second time does nothing: there are no elements left in sB
to apply map
to. You could instead do
sage: sB = list(subsets(Bob))
Now sB
is a list which can be accessed over and over again.
sage: print map(str, sB)
['[]', "['x']", "['y']", "['x', 'y']", "['z']", "['x', 'z']", "['y', 'z']", "['x', 'y', 'z']"]
sage: print map(str, sB)
['[]', "['x']", "['y']", "['x', 'y']", "['z']", "['x', 'z']", "['y', 'z']", "['x', 'y', 'z']"]
(See http://stackoverflow.com/questions/1271320/reseting-generator-object-in-python for a related question.)
2 | No.2 Revision |
sage: Bob="xyz"
sage: sB = subsets(Bob)
sage: sB
<generator object powerset at 0x18fe82f00>
At this point, sB
is a generator, and after you've done map(str,sB)
, the generator has been exhausted, so doing map(str,sB)
a second time does nothing: there are no elements left in sB
to apply map
to. You could instead do
sage: sB = list(subsets(Bob))
Now sB
is a list which can be accessed over and over again.
sage: print map(str, sB)
['[]', "['x']", "['y']", "['x', 'y']", "['z']", "['x', 'z']", "['y', 'z']", "['x', 'y', 'z']"]
sage: print map(str, sB)
['[]', "['x']", "['y']", "['x', 'y']", "['z']", "['x', 'z']", "['y', 'z']", "['x', 'y', 'z']"]
(See http://stackoverflow.com/questions/1271320/reseting-generator-object-in-python for a related question.)