python - how to make child of a list become a variable in python

Question

i'm trying to make a web only using couchdb and couchapp...
but for some reason i need external process using python..
and now i'm stuck how to handle post variable in python...

i'v read this(and it works) and this...

but i want it like this :

>>> a = {"success":1,"data":{"var1":1,"var2":2,"var3":3}}
>>> a["data"]["var2"]
2
>>> var2

Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    var2
NameError: name 'var2' is not defined
>>> for key, value in a["data"].items():
    print  (key, value)
('var1', 1)
('var3', 3)
('var2', 2)
>>> var1

Traceback (most recent call last):
  File "<pyshell#6>", line 1, in <module>
    var1
NameError: name 'var1' is not defined
>>> 

i want, when i type var2, it return 2
in other word how to make nested child object become a variable when i don't know how much len the data.. it's because in external python, how to handle post variable is like this req["form"]["var1"]

Answer 1

you should try to update your local (not recommended) or global dictionnary with your data dictionnary

>>> a = {"success":1,"data":{"var1":1,"var2":2,"var3":3}}
>>> a["data"]["var2"]
2
>>> locals().update(a["data"])
>>> var2
2

or

>>> globals().update(a["data"])
>>> var2
2

To do this in a safe way, you have to trust the source of the data you're updating your globals dictionnary with, to avoid builtin's replacement or other funny code injections.

Answer 2

Could use the python "exec" statement to build a string and then execute it dynamically.

a = {"success":1,"data":{"var1":1,"var2":2,"var3":3}}

for key, value in a["data"].items():
    exec('%s=%s' % (key, value, ))

print 'var1:', var1
print 'var2:', var2
print 'var3:', var3

Answer 3

To do this safely, I would suggest something like:

allowed_variables = ('var1', 'var2', 'var3')

for k,v in a["data"].iteritems():
    if k in allowed_variables:
        locals.update({k:v})