compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
将 source 编译为代码或者AST对象，编译后的代码或对象可以被函数 exec()、eval() 执行。
说明
参数 source，可以是普通字符串、字节字符串或者是一个 AST（Abstract Syntax Trees） 对象。即需要动态执行的代码段。
参数 filename，代码文件名称，如果不是从文件读取代码则传递一些可辨认的值。当传入了 source 参数时，filename 参数传入空字符即可。
参数 mode，指定编译代码的种类，代码的种类有三种，分别为 'exec'、'eval'、'single'。当 source 包含流程语句时，mode 应指定为 'exec'；当 source 只包含单个表达式时，mode 应指定为 'eval'；当 source 包含交互式命令语句，mode 则指定为 'single'。
示例
>>> cc = 'for i in range(0, 5): print(i)'
>>> com = compile(cc, '', 'exec')
>>> exec(com)
0
1
2
3
4
>>> cc = '2 + 3'
>>> com = compile(cc, '', 'eval')
>>> eval(com)
5
>>> cc = 'name = input("please input your name:")'
>>> com = compile(cc, '', 'single')
>>> exec(com)
please input your name:tim
>>> name
'tim'
>>>
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.
The argument optimize specifies the optimization level of the compiler; the default value of -1
selects the optimization level of the interpreter as given by -O
options. Explicit levels are 0
(no optimization; debug
is true), 1
(asserts are removed, debug
is false) or 2
(docstrings are removed too).
This function raises SyntaxError
if the compiled source is invalid, and ValueError
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.
