On Sun, Aug 3, 2008 at 8:29 PM, Antoine Pitrou <[EMAIL PROTECTED]> wrote:
> In many cases there is no runtime concatenation cost.
>
>>>> def f():
> ... return "first" + "second"
> ...
>>>> import dis
>>>> dis.dis(f)
> 2 0 LOAD_CONST 3 ('firstsecond')
> 3 RETURN_VALUE
The "many cases" only extends to strings whose combined length is less
than 20 characters:
>>> dis.dis(lambda : "1234567890123456789" + "0")
1 0 LOAD_CONST 2 ('12345678901234567890')
3 RETURN_VALUE
>>> dis.dis(lambda : "1234567890123456789" + "01")
1 0 LOAD_CONST 0 ('1234567890123456789')
3 LOAD_CONST 1 ('01')
6 BINARY_ADD
7 RETURN_VALUE
Adjacent string concentation works on arbitrary length string constants:
>>> dis.dis(lambda : "12345678901234567890" "12345678901234567890")
1 0 LOAD_CONST 0
('1234567890123456789012345678901234567890')
3 RETURN_VALUE
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