Creating a local variable with a parameterized name

[Michael Ross]

I'm new to this, so I hope I'm not missing something obvious...

I want to create a local variable with a passed in name.

I realize I can do the following:

>>> def f(varname):
             cmd = '%s = 123' % varname
             exec(cmd)
             cmd = 'print %s' % varname
             exec(cmd)

>>> f('mike')
123
>>>

But exec needs to invoke the parser, which seems to be an extremely
costly thing to do.

It seems local variables are stored in a special, inaccesible (from
python) place in the frame object (I've been looking at
PyFrame_FastToLocals and PyFrame_LocalsToFast). Do I need to write C
code to do this?  A builtin to do this would be nice...

Thanks in advance!
Mike Ross