python - exec a global variable from an extern module -

i have extern module want set "exec" expressions global (because need pass strings variables names)

so, have function like

def fct_in_extern_module():     exec 'a = 42' in globals()     return none

and in main script have

import extern_module extern_module.fct_in_extern_module()

thus, why have

nameerror: name 'a' not defined

while if (in main script)

def fct_in_main():     exec 'b = 42' in globals()  fct_in_main()  >>> b 42

any idea how can affect set string 'a' variable name in extern module ?

thanks !

globals() means "the globals dict of this module". thus, way have chosen code extern_module.py not affect globals dict of other module.

one way fix: define as:

def fct_in_extern_module(where):     exec 'a = 42' in

and call as:

extern_module.fct_in_extern_module(globals())

of course, usual, exec not best way solve problem. better:

def fct_in_extern_module(where):     where['a'] = 42

faster , cleaner.

Panthy J