Python Forum

>>> a = [1, 2, 4, 5]
>>> def az():
            x * 2

>>> q = map(az, [2, 3, 4])
>>> list(q)
[None, None, None]

>>> def az(x):
...   return x*2
... 
>>> q = map(az, [2, 3, 4])
>>> list(q)
[4, 6, 8]

>>> def az(x):
return x*2

>>> q = map(az, [2, 3, 4])
>>> q
[4, 6, 8]

(Mar-27-2017, 12:10 PM)buran Wrote: [ -> ]just to mention that there is no need to explicitly convert the result to list

# Python 3.6
>>> def az(x):
...     return x*2
... 
>>> q = map(az, [2, 3, 4])
>>> q
<map object at 0x049C8EB0>
>>> list(q)
[4, 6, 8]

# Python 2.7
>>> def az(x):
...     return x * 2
...     
>>> q = map(az, [2, 3, 4])
>>> q
[4, 6, 8]

(Mar-27-2017, 01:53 PM)snippsat Wrote: [ -> ]Python 3 has changed a lot buran 

Built-ins like range, map, zip, filter become iterables in 3.x to conserve space,
rather than producing a result list all at once in memory.