python中獲取當前位置所在的行號和函數名

對於python，這幾天一直有兩個問題在困擾我:

• 1.python中沒辦法直接取得當前的行號和函數名。這是有人在論壇裏提出的問題，底下一羣人只是在猜測python爲什麼不像__file__一樣提供__line__和__func__，但是卻最終也沒有找到解決方案。
• 2.如果一個函數在不知道自己名字的情況下，怎麼才能遞歸調用自己。這是我一個同事問我的，其實也是獲取函數名，但是當時也是回答不出來。

但是今晚！所有的問題都有了答案。
一切還要從我用python的logging模塊說起，logging中的format中是有如下選項的:

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%(name)s            Name of the logger (logging channel) %(levelno)s         Numeric logging level for the message (DEBUG, INFO,                     WARNING, ERROR, CRITICAL) %(levelname)s       Text logging level for the message ("DEBUG", "INFO",                     "WARNING", "ERROR", "CRITICAL") %(pathname)s        Full pathname of the source file where the logging                     call was issued (if available) %(filename)s        Filename portion of pathname %(module)s          Module (name portion of filename) %(lineno)d          Source line number where the logging call was issued                     (if available) %(funcName)s        Function name %(created)f         Time when the LogRecord was created (time.time()                     return value) %(asctime)s         Textual time when the LogRecord was created %(msecs)d           Millisecond portion of the creation time %(relativeCreated)d Time in milliseconds when the LogRecord was created,                     relative to the time the logging module was loaded                     (typically at application startup time) %(thread)d          Thread ID (if available) %(threadName)s      Thread name (if available) %(process)d         Process ID (if available) %(message)s         The result of record.getMessage(), computed just as                     the record is emitted

也就是說，logging是能夠獲取到調用者的行號和函數名的，那會不會也可以獲取到自己的行號和函數名呢？
我們來看一下源碼，主要部分如下:

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def currentframe():     """Return the frame object for the caller's stack frame."""     try:         raise Exception     except:         return sys.exc_info()[2].tb_frame.f_back def findCaller(self):     """     Find the stack frame of the caller so that we can note the source     file name, line number and function name.     """     f = currentframe()     #On some versions of IronPython, currentframe() returns None if     #IronPython isn't run with -X:Frames.     if f is not None:         f = f.f_back     rv = "(unknown file)", 0, "(unknown function)"     while hasattr(f, "f_code"):         co = f.f_code         filename = os.path.normcase(co.co_filename)         if filename == _srcfile:             f = f.f_back             continue         rv = (co.co_filename, f.f_lineno, co.co_name)         break     return rv def _log(self, level, msg, args, exc_info=None, extra=None):     """     Low-level logging routine which creates a LogRecord and then calls     all the handlers of this logger to handle the record.     """     if _srcfile:         #IronPython doesn't track Python frames, so findCaller throws an         #exception on some versions of IronPython. We trap it here so that         #IronPython can use logging.         try:             fn, lno, func = self.findCaller()         except ValueError:             fn, lno, func = "(unknown file)", 0, "(unknown function)"     else:         fn, lno, func = "(unknown file)", 0, "(unknown function)"     if exc_info:         if not isinstance(exc_info, tuple):             exc_info = sys.exc_info()     record = self.makeRecord(self.name, level, fn, lno, msg, args, exc_info, func, extra)     self.handle(record)

我簡單解釋一下，實際上是通過在currentframe函數中拋出一個異常，然後通過向上查找的方式，找到調用的信息。其中

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1	rv = (co.co_filename, f.f_lineno, co.co_name)

的三個值分別爲文件名，行號，函數名。(可以去http://docs.python.org/library/sys.html來看一下代碼中幾個系統函數的說明)
OK，如果已經看懂了源碼，那獲取當前位置的行號和函數名相信也非常清楚了，代碼如下:

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#!/usr/bin/python # -*- coding: utf-8 -*- ''' #============================================================================= #  Author:          dantezhu - http://www.vimer.cn #  Email:           [email protected] #  FileName:        xf.py #  Description:     獲取當前位置的行號和函數名 #  Version:         1.0 #  LastChange:      2010-12-17 01:19:19 #  History:         #============================================================================= ''' import sys def get_cur_info():     """Return the frame object for the caller's stack frame."""     try:         raise Exception     except:         f = sys.exc_info()[2].tb_frame.f_back     return (f.f_code.co_name, f.f_lineno)    def callfunc():     print get_cur_info()       if __name__ == '__main__':     callfunc()

輸入結果是:

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1	('callfunc', 24)

符合預期~~
哈哈，OK！現在應該不用再抱怨取不到行號和函數名了吧~

=============================================================================
後來發現，其實也可以有更簡單的方法，如下:

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import sys def get_cur_info():     print sys._getframe().f_code.co_name     print sys._getframe().f_back.f_code.co_name get_cur_info()

 

 

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另外,利用python的 inspect 模塊中的getframeinfo也可以得到.

inspect.getframeinfo( frame [, context ])

Get information about a frame or traceback object. A 5-tuple is returned, the last five elements of the frame’s frame record.

Changed in version 2.6: Returns a named tuple Traceback(filename, lineno, function, code_context, index).