英文文檔: compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1) ...
英文文檔:
compile
(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)
- Compile the source into a code or AST object. Code objects can be executed by
exec()
oreval()
. source can either be a normal string, a byte string, or an AST object. Refer to theast
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 thanNone
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 are0
(no optimization;__debug__
is true),1
(asserts are removed,__debug__
is false) or2
(docstrings are removed too). - This function raises
SyntaxError
if the compiled source is invalid, andValueError
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 thecode
module. - Changed in version 3.2: Allowed use of Windows and Mac newlines. Also input in
'exec'
mode does not have to end in a newline anymore. Added the optimize parameter. - Changed in version 3.5: Previously,
TypeError
was raised when null bytes were encountered in source. - 說明:
- 1. 將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。
- 2. 參數source:字元串或者AST(Abstract Syntax Trees)對象。即需要動態執行的代碼段。
- 3. 參數 filename:代碼文件名稱,如果不是從文件讀取代碼則傳遞一些可辨認的值。當傳入了source參數時,filename參數傳入空字元即可。
- 4. 參數model:指定編譯代碼的種類,可以指定為 ‘exec’,’eval’,’single’。當source中包含流程語句時,model應指定為‘exec’;當source中只包含一個簡單的求值表達式,model應指定為‘eval’;當source中包含了互動式命令語句,model應指定為'single'。
>>> #流程語句使用exec >>> code1 = 'for i in range(0,10): print (i)' >>> compile1 = compile(code1,'','exec') >>> exec (compile1) 0 1 2 3 4 5 6 7 8 9 >>> #簡單求值表達式用eval >>> code2 = '1 + 2 + 3 + 4' >>> compile2 = compile(code2,'','eval') >>> eval(compile2) 10 >>> #交互語句用single >>> code3 = 'name = input("please input your name:")' >>> compile3 = compile(code3,'','single') >>> name #執行前name變數不存在 Traceback (most recent call last): File "<pyshell#29>", line 1, in <module> name NameError: name 'name' is not defined >>> exec(compile3) #執行時顯示交互命令,提示輸入 please input your name:'pythoner' >>> name #執行後name變數有值 "'pythoner'"