我可以從字符串

Question

動態創建模塊級功能對象例如，

我想創建一個函數對象。

mystr = \ 
""" 
def foo(a=1): 
    print a 
    pass 
""" 

但是，使用編譯（myStr中）將只給我一個代碼對象。我想擁有模塊級別的函數對象，就像字符串是源代碼的一部分。

這可以實現嗎？

Answer 1

exec mystr

將執行你給的代碼。

Answer 2

是使用exec：

>>> mystr = \ 
""" 
def foo(a=1): 
    print a 
    pass 
""" 
>>> exec mystr 
>>> foo 
<function foo at 0x0274F0F0> 

Answer 3

您還可以使用compile在這裏，它支持像exec，eval，single模式：

In [1]: mystr = \ 
""" 
def foo(a=1): 
     print a 
     pass 
""" 
    ...: 

In [2]: c=compile(mystr,"",'single') 

In [3]: exec c 

In [4]: foo 
Out[4]: <function __main__.foo> 

幫助上compile：

In [5]: compile? 
Type:  builtin_function_or_method 
String Form:<built-in function compile> 
Namespace: Python builtin 
Docstring: 
compile(source, filename, mode[, flags[, dont_inherit]]) -> code object 

Compile the source string (a Python module, statement or expression) 
into a code object that can be executed by the exec statement or eval(). 
The filename will be used for run-time error messages. 
The mode must be 'exec' to compile a module, 'single' to compile a 
single (interactive) statement, or 'eval' to compile an expression. 
The flags argument, if present, controls which future statements influence 
the compilation of the code. 
The dont_inherit argument, if non-zero, stops the compilation inheriting 
the effects of any future statements in effect in the code calling 
compile; if absent or zero these statements do influence the compilation, 
in addition to any features explicitly specified.