C#3.0 and lambdas

Christophe chris.cavalaria at free.fr
Thu Sep 22 15:11:09 CEST 2005


Steven Bethard a écrit :
> Steven D'Aprano wrote:
> 
>> I would love to see your test code and profiling results that demonstrate
>> that explicit tuple unpacking in the body of a function is faster than
>> tuple unpacking (implicit or explicit) in the header of a function.
> 
> 
> Should be pretty close.  I believe the byte-code is nearly identical:

You forgot the most important function : f3

 >>> def f1((x,y)):
...     print x,y
...
 >>> def f2(x_y):
...     x,y = x_y
...     print x,y
...
 >>> def f3(x_y):
...     print x_y[0], x_y[1]
...
 >>> import dis
 >>> dis.dis(f1)
   1           0 LOAD_FAST                0 (.0)
               3 UNPACK_SEQUENCE          2
               6 STORE_FAST               1 (x)
               9 STORE_FAST               2 (y)

   2          12 LOAD_FAST                1 (x)
              15 PRINT_ITEM
              16 LOAD_FAST                2 (y)
              19 PRINT_ITEM
              20 PRINT_NEWLINE
              21 LOAD_CONST               0 (None)
              24 RETURN_VALUE
 >>> dis.dis(f2)
   2           0 LOAD_FAST                0 (x_y)
               3 UNPACK_SEQUENCE          2
               6 STORE_FAST               2 (x)
               9 STORE_FAST               1 (y)

   3          12 LOAD_FAST                2 (x)
              15 PRINT_ITEM
              16 LOAD_FAST                1 (y)
              19 PRINT_ITEM
              20 PRINT_NEWLINE
              21 LOAD_CONST               0 (None)
              24 RETURN_VALUE
 >>> dis.dis(f3)
   2           0 LOAD_FAST                0 (x_y)
               3 LOAD_CONST               1 (0)
               6 BINARY_SUBSCR
               7 PRINT_ITEM
               8 LOAD_FAST                0 (x_y)
              11 LOAD_CONST               2 (1)
              14 BINARY_SUBSCR
              15 PRINT_ITEM
              16 PRINT_NEWLINE
              17 LOAD_CONST               0 (None)
              20 RETURN_VALUE
 >>>



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