my apologies, to Fredrick, my response when solely to him. reply below, hopefully keeping thread intact.
On Mon, Jul 21, 2008 at 12:28 PM, Jeff Dyke <[EMAIL PROTECTED]> wrote: > On Mon, Jul 21, 2008 at 10:19 AM, Fredrik Lundh <[EMAIL PROTECTED]> wrote: >> Jeff Dyke wrote: >> >>> I've come across an error that i'm not yet able to create a test case >>> for but wanted to get see if someone could shed light on this. >>> >>> I have imported a module at the top of my file with >>> import mymodulename >>> >>> this module is used many times in the current file successfully, but >>> then I attempt to use it one more time and get: UnboundLocalError: >>> local variable 'mymodulename' referenced before assignment >> >> Let me guess: you've done >> >> def myfunc(): >> print mymodulename >> import mymodulename > > actually no, the only things in that fucntion were. > print globals().keys() - i see it here > print mymodulename - it fails here. > > the `import mymodulename` statement is at the very top of the file. > > plus the processing that was attempted after. in fact in the calling > method i was able to execute print mymodulename and it printed the > expected python output. > >> >> or something similar? Getting an exception in this case is the excepted >> behaviour; the reason being that a variable in a block only belongs to a >> single scope. for the entire block. For details, see: >> >> http://docs.python.org/ref/naming.html >> >> Especially this section: >> >> "If a name binding operation occurs anywhere within a code block, all uses >> of the name within the block are treated as references to the current block. >> This can lead to errors when a name is used within a block before it is >> bound. This rule is subtle. Python lacks declarations and allows name >> binding operations to occur anywhere within a code block. The local >> variables of a code block can be determined by scanning the entire text of >> the block for name binding operations." >> >> To fix this, mark the name as global: >> >> def myfunc(): >> global mymodulename # I mean the global name! >> print mymodulename >> import mymodulename > > > So i went back to check that the name 'mymodulename' was not getting > overwritten by something else and the error went away. I've been > working on something else entirely for the past few hours and have > changed none of the code...and now it works. which is even more > troublesome then the error itself. > > Follow on question. If this name, mymodulename, was imported in some > other module.fucntion local to a function like > def anotherfunc(): > import mymodulename > > would that remove it from the globals() and save it to a locals() ? I > would assume the answer to be no. > > Thanks for you response. > Jeff > > >> >> </F> >> >> -- >> http://mail.python.org/mailman/listinfo/python-list >> > -- http://mail.python.org/mailman/listinfo/python-list
