On 30 May 2013 21:35, eryksun <eryk...@gmail.com> wrote:
> In terms of sequence methods, it's inplace concatenation. On their
> own, immutable string types only support regular concatenation, but
> the interpreter can evaluate the concatenation inplace for special
> cases. Specifically, it can resize the target string in an INPLACE_ADD
> if it's not interned and has only *one* reference.
It's also for BINARY_ADD in the form a = a + b:
$ python
Python 2.7.3 (default, Sep 26 2012, 21:51:14)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> s = 'abcdefgh' * 128
>>> id_s = id(s)
>>> s = s + 'spam'
>>> print(id(s) == id_s)
True
A rare case of me actually using the dis module:
>>> def f():
... s = s + 'spam'
...
>>> import dis
>>> dis.dis(f)
2 0 LOAD_FAST 0 (s)
3 LOAD_CONST 1 ('spam')
6 BINARY_ADD
7 STORE_FAST 0 (s)
10 LOAD_CONST 0 (None)
13 RETURN_VALUE
Oscar
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