[python] Should I use Python 32bit or Python 64bit

I have a win7 64bit installation. Must I use Python 64bit? What are the differences between the 32bit and 64bit Python versions anyway? Do different Python packages (such as south, django, mysqldb etc) support only 32bit/64bit?

You do not need to use 64bit since windows will emulate 32bit programs using wow64. But using the native version (64bit) will give you more performance.

Use the 64 bit version only if you have to work with heavy amounts of data, in that scenario, the 64 bits performs better with the inconvenient that John La Rooy said; if not, stick with the 32 bits.

Machine learning packages like tensorflow 2.x are designed to work only on 64 bit Python as they are memory intensive.

In my experience, using the 32-bit version is more trouble-free. Unless you are working on applications that make heavy use of memory (mostly scientific computing, that uses more than 2GB memory), you're better off with 32-bit versions because:

1. You generally use less memory.
2. You have less problems using COM (since you are on Windows).
3. If you have to load DLLs, they most probably are also 32-bit. Python 64-bit can't load 32-bit libraries without some heavy hacks running another Python, this time in 32-bit, and using IPC.
4. If you have to load DLLs that you compile yourself, you'll have to compile them to 64-bit, which is usually harder to do (specially if using MinGW on Windows).
5. If you ever use PyInstaller or py2exe, those tools will generate executables with the same bitness of your Python interpreter.

I had trouble running python app (running large dataframes) in 32 - got MemoryError message, while on 64 it worked fine.