On 3/26/12 12:45 PM, redstone-c...@163.com wrote:
I know the print statement produces the same result when both of these two
instructions are executed ,I just want to know Is there any difference between
print 3 and print '3' in Python ?
Yes, there is a difference, but not much.
[~]
|6> import dis
[~]
|7> dis.disassemble(compile('print 3', '<string>', 'exec'))
1 0 LOAD_CONST 0 (3)
3 PRINT_ITEM
4 PRINT_NEWLINE
5 LOAD_CONST 1 (None)
8 RETURN_VALUE
[~]
|8> dis.disassemble(compile('print "3"', '<string>', 'exec'))
1 0 LOAD_CONST 0 ('3')
3 PRINT_ITEM
4 PRINT_NEWLINE
5 LOAD_CONST 1 (None)
8 RETURN_VALUE
As you can see, the only difference is in the first instruction. Both of these
put the object that you specified by the literal onto the stack. The difference
is that one is the int object specified by the literal 3 and the other is the
str object specified by the literal "3". Both of these objects happen to give
the same __str__ output, so that's what gets printed.
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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