On 11/02/2014 18:53, wxjmfa...@gmail.com wrote:
Le lundi 10 février 2014 15:43:08 UTC+1, Tim Chase a écrit :
On 2014-02-10 06:07, wxjmfa...@gmail.com wrote:
Python does not save memory at all. A str (unicode string)
uses less memory only - and only - because and when one uses
explicitly characters which are consuming less memory.
Not only the memory gain is zero, Python falls back to the
worse case.
sys.getsizeof('a' * 1000000)
1000025
sys.getsizeof('a' * 1000000 + 'oe')
2000040
sys.getsizeof('a' * 1000000 + 'oe' + '\U00010000')
4000048
If Python used UTF-32 for EVERYTHING, then all three of those cases
would be 4000048, so it clearly disproves your claim that "python
does not save memory at all".
The opposite of what the utf8/utf16 do!
sys.getsizeof(('a' * 1000000 + 'oe' +
'\U00010000').encode('utf-8'))
1000023
sys.getsizeof(('a' * 1000000 + 'oe' +
'\U00010000').encode('utf-16'))
2000025
However, as pointed out repeatedly, string-indexing in fixed-width
encodings are O(1) while indexing into variable-width encodings (e.g.
UTF8/UTF16) are O(N). The FSR gives the benefits of O(1) indexing
while saving space when a string doesn't need to use a full 32-bit
width.
A utf optimizes the memory and the performance at the same time.
It behaves like a mathematical operator, a unique operator for
a unique set of elements. Unbeatable.
The FSR is an exclusive or mechanism. I you wish to
same memory, you have to encode, and if you are encoding,
maybe because you have to, one loses performance. Paradoxal.
Your O(1) indexing works only and only because and
when you are working explicitly with a "static" unicode
string you never touch.
It's a little bit the the "corresponding" performance
case of the memory case.
jmf
Why are you so rude as to continually post your nonsense here that not a
single person believes, and at the same time still quite deliberately
use gg to post it with double line spacing. If you lack the courtesy to
stop the former, please have the courtesy to stop the latter.
--
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.
Mark Lawrence
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