Perl's @foo[3,7,1,-1] ?

J. Cliff Dyer jcd at
Mon Jun 22 10:12:08 EDT 2009

On Mon, 2009-06-22 at 14:57 +0200, Jean-Michel Pichavant wrote:
> J. Cliff Dyer wrote:
> > On Wed, 2009-06-17 at 14:13 +0200, Jean-Michel Pichavant wrote:
> >   
> >> On Wed, Jun 17, 2009 at 04:14, Steven D'Aprano wrote:
> >>     
> >>>> What's np.arange?
> >>>>     
> >>>>         
> >>> import numpy as np
> >>>
> >>> --
> >>> Pierre "delroth" Bourdon <delroth at>
> >>> Étudiant à l'EPITA / Student at EPITA
> >>>   
> >>>       
> >> Perfect example of why renaming namespaces should be done only when 
> >> absolutely required, that is, almost never.
> >>
> >> Jean-Michel
> >>     
> >
> > I disagree.  Renaming namespaces should always be done if it will help
> > stop people from doing a 'from package import *'.  However, example code
> > should always include relevant imports.
> >
> > Cheers,
> > Cliff
> >
> >
> >   
> The import * should not used if possible, I totally agree on that point, 
> but there's no need to rename namespaces for that.
> br
> Jean-Michel

Technically, no.  But we're dealing with people, who are notoriously
*un*technical in their behavior.  A person is much more likely to
develop bad habits if the alternative means more work for them.  The
reason people do `from foo import *` is that they don't want to type
more than they have to.  If they can write a one or two letter
namespace, they're likely to be happy with that trade-off.  If the
alternative is to write out long module names every time you use a
variable, they'll tend to develop bad habits.  To paraphrase Peter
Maurin, coding guidelines should have the aim of helping to "bring about
a world in which it is easy to be good."

I don't really see much problem with renaming namespaces: For people
reading the code, everything is explicit, as you can just look at the
top of the module to find out what module a namespace variable
represent; the local namespace doesn't get polluted with God knows what
from God knows where; and code remains succinct.

I've found in my own code that using, for example, the name `sqlalchemy`
in my code means that I have to go through painful contortions to get
your code down to the PEP-8 recommended 80 characters per line.  The
resulting mess of multi-line statements is significantly less readable
than the same code using the abbreviation `sa`.

Do you have an argument for avoiding renaming namespaces?  So far the
only example you provided is a code fragment that doesn't run.  I don't
disagree with you on that example; referring to numpy as np without
telling anyone what np refers to is a bad idea, but no functioning piece
of code could reasonably do that.


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