The canonical way to find out where a command is found on the path with with the Bourne shell built-in,
$ command -v python
/usr/local/anaconda/bin/python
(BTW, don't use which; let the shell tell you what it's doing.)
It could easily be that Python2 is on your path, but later in the list than the one that's being found. It could also be that the shell's cache of found executables needs updating:
$ help hash
hash: hash [-lr] [-p pathname] [-dt] [name ...]
Remember or display program locations.
...
-d forget the remembered location of each NAME
$ hash -d python; command -v python
/usr/local/anaconda/bin/python
To display the path in a more friendly way:
$ echo $PATH | tr : \\n
/usr/local/anaconda/bin
/usr/local/sbin
/usr/local/bin
/usr/sbin
/usr/bin
/sbin
/bin
/usr/games
/usr/local/games
You may want to re-arrange your path. Another trick I sometimes use is to rename the system-provided executable, perhaps by capitalizing it, so it's still available but won't be found without special effort.