[Tutor] using dynamic import statements

[Hugo Arts]

On Mon, Jul 9, 2012 at 3:10 AM, Chris Hare <chare at labr.net> wrote:

>
> Here is what I want to do:
>
> I have a bunch of modules to import. instead of duplicating a lot of code
> for each import, I want to do something like this:
>
> importList = [ "sys", "os", "imp", "stat", "re", "webbrowser", "Image",
>  "StringIO", "shutil", "datetime" ]
>
> for object in importList:
>         try:
>                 if debug == "ON":
>                         print "Importing module %s" % (object)
>                 exec( "import  " + object)
>         except ImportError as error:
>                 print "%s %s requires the Python %s library.  " % (
> appName,
>
> str(appVersion), object )
>                 print "An error occurred when attempting to load the
> library.  The error was '%s'." % ( error )
>                 exit()
>
> Everything "appears" to run okay, however, when the first piece of code
> that relies upon one of these imported modules is executed, I get an error:
>
> Traceback (most recent call last):
>   File "a.py", line 122, in <module>
>     imp.load_module(object,fp,pathName,description)
>   File "./Modules/functions.py", line 133, in <module>
>     def special_match(strg, search=re.compile(r'[^a-zA-Z0-9\.\
> \-\#\$\*\@\!\%\^\&]').search):
> NameError: name 're' is not defined
>
> Is is possible to do what I am trying to do, or am I doing something wrong?
>
>
 Yes, it is possible, but you are doing something wrong. Don't use exec()
for this, it's unnecessary. You can make this work with the exec function,
but the function you really want is called __import__(). It's documented
here: http://docs.python.org/library/functions.html#__import__

HTH,
Hugo
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