python 2.7

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"Compatible" might be the wrong word, because Sage uses its own Python.

Currently, as of Sage 4.8, the internal Python version is 2.6.4. However, this should change (assuming everything works out!) in Sage 5.0, which is currently in beta. 5.0 should have Python 2.7.2, and you can verify this at test.sagenb.org, if you like-- log in and run "import sys; print sys.version".

It'll be nice to have dict comprehensions and collections.Counter..

DSM's answer is the best. However, just in case this is what you are asking, some people do use Sage with system components, including Python, with things like Sage on Gentoo and the related lmonade. There also used to be a Debian version.