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ramalho/constfold.rst

Created July 9, 2014 15:10
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Constant folding in Python: think about why the bytecodes generated for f() and g() are different
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constfold.rst

>>> import dis >>> def f(x): ... return 1+2+3+4+x ... >>> f(5) 15 >>> dis.dis(f) 2 0 LOAD_CONST 7 (10) 3 LOAD_FAST 0 (x) 6 BINARY_ADD 7 RETURN_VALUE >>> def g(x): ... return x+1+2+3+4 ... >>> dis.dis(g) 2 0 LOAD_FAST 0 (x) 3 LOAD_CONST 1 (1) 6 BINARY_ADD 7 LOAD_CONST 2 (2) 10 BINARY_ADD 11 LOAD_CONST 3 (3) 14 BINARY_ADD 15 LOAD_CONST 4 (4) 18 BINARY_ADD 19 RETURN_VALUE

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