Python 3 FAQ¶
Contents
What Python 3 versions are supported?¶
PyMongo supports Python 3.x where x >= 2.
Are there any PyMongo behavior changes with Python 3?¶
Only one intentional change. Instances of bytes
are encoded as BSON type 5 (Binary data) with subtype 0.
In Python 3 they are decoded back to bytes
. In
Python 2 they will be decoded to Binary
with subtype 0.
For example, let’s insert a bytes
instance using Python 3 then
read it back. Notice the byte string is decoded back to bytes
:
Python 3.2.5 (default, Feb 26 2014, 12:40:25)
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pymongo
>>> c = pymongo.MongoClient()
>>> c.test.bintest.insert_one({'binary': b'this is a byte string'}).inserted_id
ObjectId('4f9086b1fba5222021000000')
>>> c.test.bintest.find_one()
{'binary': b'this is a byte string', '_id': ObjectId('4f9086b1fba5222021000000')}
Now retrieve the same document in Python 2. Notice the byte string is decoded
to Binary
:
Python 2.7.6 (default, Feb 26 2014, 10:36:22)
[GCC 4.7.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pymongo
>>> c = pymongo.MongoClient()
>>> c.test.bintest.find_one()
{u'binary': Binary('this is a byte string', 0), u'_id': ObjectId('4f9086b1fba5222021000000')}