Как насчет несложного быстрого ответа? Нет map
, нет for
петли, ...
>>> s = "Foo Bar " * 5
>>> s
'Foo Bar Foo Bar Foo Bar Foo Bar Foo Bar '
>>> ''.join(s.split()).lower()
'foobarfoobarfoobarfoobarfoobar'
>>>
[Python 2.7.1]
>python -mtimeit -s"s='The quick brown Fox jumped over the lazy dogs'" "''.join(c.lower() for c in s if not c.isspace())"
100000 loops, best of 3: 11.7 usec per loop
>python27\python -mtimeit -s"s='The quick brown Fox jumped over the lazy dogs'" "''.join( i.lower() for i in s.split() )"
100000 loops, best of 3: 3.11 usec per loop
>python27\python -mtimeit -s"s='The quick brown Fox jumped over the lazy dogs'" "''.join( map(str.lower, s.split() ) )"
100000 loops, best of 3: 2.43 usec per loop
>\python27\python -mtimeit -s"s='The quick brown Fox jumped over the lazy dogs'" "''.join(s.split()).lower()"
1000000 loops, best of 3: 1 usec per loop