What does apt-get install 3.5 do?

Question

I asked a question here about accidentally calling apt-get install python 3.5(space intentional) on Linux Mint. I learned, or was reminded that it was the same as calling ...install python, then calling ...install 3.5.

My new question is this:

I have python 3.5 installed on my Linux Mint system, via apt-get install python3.5

If I type apt-get install 3.5, it seems like a shorthand for python 3.5, because I get a list of already installed packages that have the python 3.5 name in them.

However, I also get a list of NEW packages;

The following NEW packages will be installed:
blt idle-python3.5 libpython3.5 libpython3.5-dbg libpython3.5-dev
libpython3.5-gdbm libpython3.5-gdbm-dbg libpython3.5-testsuite
libpython3.5-tk libpython3.5-tk-dbg python3.5-complete python3.5-dbg
python3.5-dev python3.5-doc python3.5-examples python3.5-gdbm
python3.5-gdbm-dbg python3.5-tk python3.5-tk-dbg python3.5-venv

So why if I have python 3.5 installed does typing install 3.5show new packages wherein typing install python3.5 does not? What is the relationthip between python3.5 and 3.5, and what (if any) deleterious affect does installing just 3.5 have?

Answer 1

When you use command apt-get install 3.5 or (in my case)sudo apt-get install 3.5, system checks for all packages with 3.5 in their name.

It basically uses a regex to find all packages(not only Python packages) that match the pattern 3.5

Same can be seen in the screenshot I have attached: