On 07Jan2017 19:45, jim <jf_byr...@comcast.net> wrote:
On 01/07/2017 05:58 PM, Clint Moyer wrote:
So to minimize your issues with installing Python packages, take the
path of least resistance and install through your system repo. And use
Python2 or Python3 explicitly to avoid conflicts.
As I mentioned in another post, most of the more popular modules I had
installed on my old system using pip are available in the repository
and I will use the repository to install them on the new system. I now
understand that using sudo is a bad idea.
Cool.
One question from the earlier post that did not get answered concerned
upgrading a repository installed module with pip.
I would recommend not. As soon as you get there:
- if the vendor updates it, use apt-get (I know this doesn't fit your
situation with Ubuntu 16.04 LTS)
- if you want a more modern version, now is the time to use virtualenv
The thing about LTS is that the vendor guarentees its stability. If you upgrade
the vendor installed package using /usr/bin/pip (or pip3) as root, you're
replacing the vendor supplied module with a newer one, which may break vendor
supplied packages which use that module expected the _old_ behaviour.
So endeavour to leave the vendor suppplied stuff entirely alone except for
apt-get style updates.
Instead, make a virtualenv an upgrade it with a newer package.
To get started on the new system I installed pip3 from the repository. The
first time I used it to install a module it said a newer version was available
and gave the command to update it. What are the consequences of using pip to
upgrade repository installed modules?
In theory, if the newer version of the module installs a breaking change it can
break things in the system which might use that module and expect its old
behaviour. Also, _sometimes_, vendors supply patches versions of packages,
possibly including python modules. If they're modified/patched, there is
probably a reason. You'd be undoing that patch.
I ask because 16.04 is LTS and won't be getting version upgrades
unless they are security related. Also pandas is in the repositories but the
module pandas-datareader, which I may need to use, is not.
Again: make a virtualenv as yourself.
Its pip can be run as yourself, therefore cannot accidentally modify system
module. It's pip can freely upgrade a older module. If you install a module
_not_ supplied by the vendor, the virtualenv pip can freely do that, and _also_
upgrade a required module should that be required (PyPI package definitions let
a module specify required revisions of other modules it may use).
Cheers,
Cameron Simpson <c...@zip.com.au>
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