python内置函數3-compile()

Help on built-in function compile in module __builtin__:

compile(...)

    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.

compile(source, filename, mode[, flags[, dont_inherit]])

Compile the source into a code or AST object. Code objects can be executed by an exec statement or evaluated by a call to eval(). source can either be a Unicode string, a Latin-1 encoded string or an AST object. Refer to the ast module documentation for information on how to work with AST objects.

The filename argument should give the file from which the code was read; pass some recognizable value if it wasn’t read from a file ('<string>' is commonly used).

The mode argument specifies what kind of code must be compiled; it can be 'exec' if source consists of a sequence of statements, 'eval' if it consists of a single expression, or 'single' if it consists of a single interactive statement (in the latter case, expression statements that evaluate to something other than None will be printed).

The optional arguments flags and dont_inherit control which future statements (see PEP 236) affect the compilation of source. If neither is present (or both are zero) the code is compiled with those future statements that are in effect in the code that is calling compile(). If the flags argument is given and dont_inherit is not (or is zero) then the future statements specified by the flags argument are used in addition to those that would be used anyway. If dont_inherit is a non-zero integer then the flags argument is it – the future statements in effect around the call to compile are ignored.

Future statements are specified by bits which can be bitwise ORed together to specify multiple statements. The bitfield required to specify a given feature can be found as the compiler_flag attribute on the _Feature instance in the __future__ module.

This function raises SyntaxError if the compiled source is invalid, and TypeError if the source contains null bytes.

If you want to parse Python code into its AST representation, see ast.parse().

Note When compiling a string with multi-line code in 'single' or 'eval' mode, input must be terminated by at least one newline character. This is to facilitate detection of incomplete and complete statements in the code module.

compile(source, filename, mode[, flags[, dont_inherit]])

中文說明：将source編譯為代碼或者AST對象。代碼對象能夠通過exec語句來執行或者eval()進行求值。

參數source：字元串或者AST（Abstract Syntax Trees）對象。

參數filename：代碼檔案名稱，如果不是從檔案讀取代碼則傳遞一些可辨認的值。

參數model：指定編譯代碼的種類。可以指定為 ‘exec’,’eval’,’single’。

參數flag和dont_inherit：這兩個參數暫不介紹，可選參數。

版本：在python2.3、2.6、2.7、3.2中均有不同，使用時要引起注意，相容python3

>>> code="for i in range(0,10): print i"

>>> cmpcode=compile(code,'','exec')

>>> exec cmpcode

1

2

3

4

5

6

7

8

9

>>> str="3*4+5"

>>> a=compile(str,'','eval')

>>> eval(a)

17

轉載于:https://blog.51cto.com/hdlptz/1899524