Broken Python 2.6 installation on Ubuntu Linux 8.04

[Benjamin Kaplan]

On Sun, Jan 24, 2010 at 5:53 PM, John Ladasky <ladasky at my-deja.com> wrote:
> Hello everyone,
>
> I've posted this same question over on ubuntuforums.org, so I'm trying
> to get help in all of the logical places.
>
> I'm running Ubuntu Linux 8.04 (Hardy) on a fairly new x86 box, with
> two hard disks in a software RAID 1 configuration.
>
> Hardy comes with Python 2.5 as a standard package, but not 2.6.  I
> would really like to have the "combinations" function that is included
> with itertools in Python 2.6.  I tried writing a combinations function
> of my own, but it's SLOW and uses a HUGE amount of memory.
>
> So, in my case the Linux Synaptic Package Manager cannot be used to
> install Python 2.6.  I therefore attempted a manual installation.  I
> downloaded the Linux tarball for Python 2.6 from python.org.  I
> followed the installation instructions, and they appeared to execute
> fine.  But when I started IDLE, I still had Python 2.5.  No good.
>

How did you start IDLE? If you started it by going to the Applications
menu, it still points to the Python 2.5 idle. If you open up a
terminal and run idle, it should run Python 2.6. If it doesn't, make a
.bashrc file in your home directory and add the line
"$PATH=/usr/local/bin:$PATH".

> I do most of my editing in SCIte.  Apparently SCIte knows that I have
> Python 2.6, and is trying to use it. Alas, my programs depend on extra
> Python packages such as biopython, numpy and matplotlib. My Python 2.6
> distro does not have these yet. None of my programs will run from
> SCIte!

Extensions written in C must be recompiled for every version of
Python. Since you're using a version of Python not available through
the package manager, your packages are also not available through
that. You'll have to download the sources for those and compile them
by hand to. This is why most people stick with the precompiled
binaries.
>
> Looking down into the details of the install, I've discovered that
> Hardy placed the Python 2.4 and 2.5 executables in /usr/bin.  My
> Python 2.6 installation ended up in /usr/local/bin.  This may be
> contributing to my problems.
>

It shouldn't be. /usr/local/bin should already be on your path in
front of /usr/bin. If it isn't put it there (that's what the .bashrc
file I listed before does)

> Given the mess I've made by trying to just install plain-old Python, I
> don't know whether I should attempt to back out, or to press on. Can I
> convince IDLE to connect to Python 2.6?  How do I manually install
> site packages?
>

Download the package sources and compile them yourself. Python
packages have a very easy way to do that- just cd into the source
folder and run "python setup.py install"

> Alternately, I COULD upgrade my Ubuntu Linux to 9.4 (Jaunty) or 9.10
> (Karmic).  Python 2.6 comes standard with both of these.  But this is
> why I mentioned that my storage is RAID1.  Apparently, upgrading with
> RAID present is a serious headache.  The Linux wizards are supposed to
> be fixing these problems in the next release, due in April.  I could
> wait, I suppose.
>
> In the mean time, I may have to uninstall Python 2.6 and get my 2.5
> running again.  I have not found any instructions for how to do that.
>

Your Python2.5 installation is just fine. You can get to it by running
python2.5 at the command line (as opposed to "python" which should run
python2.6)

> Help!
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>