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Single leading dash in member variable names?

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  Single leading dash in member variable names? e.doxtator@gmail.com - 2012-09-11 11:45 -0700
    Re: Single leading dash in member variable names? Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-11 13:06 -0600
      Re: Single leading dash in member variable names? e.doxtator@gmail.com - 2012-09-11 13:53 -0700
        Re: Single leading dash in member variable names? Terry Reedy <tjreedy@udel.edu> - 2012-09-11 17:34 -0400
      Re: Single leading dash in member variable names? e.doxtator@gmail.com - 2012-09-11 13:53 -0700
        Re: Single leading dash in member variable names? Erik Max Francis <max@alcyone.com> - 2012-09-11 15:02 -0700
          Re: Single leading dash in member variable names? Tim Chase <python.list@tim.thechases.com> - 2012-09-12 05:49 -0500
          Re: Single leading dash in member variable names? e.doxtator@gmail.com - 2012-09-12 08:23 -0700
            Re: Single leading dash in member variable names? Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-12 10:52 -0600
            Re: Single leading dash in member variable names? mdengler@gmail.com - 2012-09-12 09:53 -0700
          Re: Single leading dash in member variable names? Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-12 09:23 -0600
      Re: Single leading dash in member variable names? aahz@pythoncraft.com (Aahz) - 2012-11-10 07:41 -0800

#28896 — Single leading dash in member variable names?

All

Python noob here.  Trying to understand a particular syntax:

class stuff:
    def __init__(self):
         self._bongo = "BongoWorld"

-----------

What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.

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#28897

On Tue, Sep 11, 2012 at 12:45 PM,  <e.doxtator@gmail.com> wrote:
> All
>
> Python noob here.  Trying to understand a particular syntax:
>
> class stuff:
>     def __init__(self):
>          self._bongo = "BongoWorld"
>
> -----------
>
> What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.

Single leading underscore is a convention indicating that the name
should be considered private and not used externally.  It's a softer
version of the double leading underscore that means basically the same
thing but has syntactic significance.

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#28900

On Tuesday, September 11, 2012 2:06:45 PM UTC-5, Ian wrote:
> On Tue, Sep 11, 2012 at 12:45 PM,  I wrote:
> 
> > All
> 
> >
> 
> > Python noob here.  Trying to understand a particular syntax:
> 
> >
> 
> > class stuff:
> 
> >     def __init__(self):
> 
> >          self._bongo = "BongoWorld"
> 
> >
> 
> > -----------
> 
> >
> 
> > What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.
> 
> 
> 
> Single leading underscore is a convention indicating that the name
> 
> should be considered private and not used externally.  It's a softer
> 
> version of the double leading underscore that means basically the same
> 
> thing but has syntactic significance.

Thank you!

PEP 8 says this is bad form.  What do you think?

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#28903

On 9/11/2012 4:53 PM, e.doxtator@gmail.com wrote:

>>> What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.

>> Single leading underscore is a convention indicating that the name
>> should be considered private and not used externally.  It's a softer
>> version of the double leading underscore that means basically the same
>> thing but has syntactic significance.

> PEP 8 says this is bad form.  What do you think?

Please quote the specific statement you want commented. The stdlib 
routinely uses _names for internal implementation objects. __ugh is 
perhaps never used.

-- 
Terry Jan Reedy

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#28901

On Tuesday, September 11, 2012 2:06:45 PM UTC-5, Ian wrote:
> On Tue, Sep 11, 2012 at 12:45 PM,  I wrote:
> 
> > All
> 
> >
> 
> > Python noob here.  Trying to understand a particular syntax:
> 
> >
> 
> > class stuff:
> 
> >     def __init__(self):
> 
> >          self._bongo = "BongoWorld"
> 
> >
> 
> > -----------
> 
> >
> 
> > What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.
> 
> 
> 
> Single leading underscore is a convention indicating that the name
> 
> should be considered private and not used externally.  It's a softer
> 
> version of the double leading underscore that means basically the same
> 
> thing but has syntactic significance.

Thank you!

PEP 8 says this is bad form.  What do you think?

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#28905

On 09/11/2012 01:53 PM, e.doxtator@gmail.com wrote:
> On Tuesday, September 11, 2012 2:06:45 PM UTC-5, Ian wrote:
>> On Tue, Sep 11, 2012 at 12:45 PM,  I wrote:
>>> What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.
>>
>> Single leading underscore is a convention indicating that the name
>> should be considered private and not used externally.  It's a softer
>> version of the double leading underscore that means basically the same
>> thing but has syntactic significance.
>
> Thank you!
>
> PEP 8 says this is bad form.  What do you think?

Where does it say that?

-- 
Erik Max Francis && max@alcyone.com && http://www.alcyone.com/max/
  San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Jabber erikmaxfrancis
   I will always remember / This moment
    -- Sade

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#28944

On 09/12/12 00:10, Dwight Hutto wrote:
> Not to jump in with another question(this seems somewhat relevant
> to the conversation, maybe not), but is this similar to a
> private,public, or protected class similar to the C type langs?

Close, but C-like languages tend to strictly enforce it, while in
Python it's more of a gentleman's agreement.  Python doesn't *stop*
you from mucking with them, but you've been advised that, if it
breaks, you get to keep both parts.

-tkc

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#28975

On Tuesday, September 11, 2012 5:02:31 PM UTC-5, Erik Max Francis wrote:
> On 09/11/2012 01:53 PM, me wrote:
> 
> > On Tuesday, September 11, 2012 2:06:45 PM UTC-5, Ian wrote:
> 
> >> On Tue, Sep 11, 2012 at 12:45 PM,  I wrote:
> 
> >>> What is the significance of the leading underscore in "self._bongo"?  I've seen this a few times and, after looking through PEP 8, I didn't see anything relevant, but I could have missed it.
> 
> >>
> 
> >> Single leading underscore is a convention indicating that the name
> 
> >> should be considered private and not used externally.  It's a softer
> 
> >> version of the double leading underscore that means basically the same
> 
> >> thing but has syntactic significance.
> 
> >
> 
> > Thank you!
> 
> >
> 
> > PEP 8 says this is bad form.  What do you think?
> 
> 
> 
> Where does it say that?

Apologies.  It's in David Goodger's "Code Like A Pythonista" in the "Naming" section. (http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#naming)

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#28984

On Wed, Sep 12, 2012 at 9:23 AM, <e.doxtator@gmail.com> wrote:
>
> On Tuesday, September 11, 2012 5:02:31 PM UTC-5, Erik Max Francis wrote:
> > On 09/11/2012 01:53 PM, me wrote:
> > > PEP 8 says this is bad form.  What do you think?
> >
> >
> >
> > Where does it say that?
>
> Apologies.  It's in David Goodger's "Code Like A Pythonista" in the "Naming" section. (http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#naming)

That's arguing against double leading underscore, not single leading
underscore.  I pretty much agree with it; I rarely use the
name-mangling syntax myself.

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#28985

On Wednesday, September 12, 2012 4:23:49 PM UTC+1, (unknown) wrote:
> [...] David Goodger's "Code Like A Pythonista" in the "Naming" section [says single leading underscore is bad form]. (http://python.net/~goodger/projects/pycon/2007/idiomatic/handout.html#naming)

Looks like it says the opposite:

"[rather than trying to hide attributes with double-leading-underscores, i]t's better to use the single-leading-underscore convention, _internal".

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#28976

On Tue, Sep 11, 2012 at 11:10 PM, Dwight Hutto <dwightdhutto@gmail.com> wrote:
> Not to jump in with another question(this seems somewhat relevant to the
> conversation, maybe not), but is this similar to a private,public, or
> protected class similar to the C type langs?

More like "this is an implementation detail and in the future it could
be changed or removed entirely without warning".  I consider them
private unless documented otherwise.

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#33089

In article <mailman.514.1347390405.27098.python-list@python.org>,
Ian Kelly  <ian.g.kelly@gmail.com> wrote:
>On Tue, Sep 11, 2012 at 12:45 PM,  <e.doxtator@gmail.com> wrote:
>>
>> Python noob here.  Trying to understand a particular syntax:
>>
>> class stuff:
>>     def __init__(self):
>>          self._bongo = "BongoWorld"
>>
>> What is the significance of the leading underscore in "self._bongo"?
>> I've seen this a few times and, after looking through PEP 8, I didn't
>> see anything relevant, but I could have missed it.
>
>Single leading underscore is a convention indicating that the name
>should be considered private and not used externally.  It's a softer
>version of the double leading underscore that means basically the same
>thing but has syntactic significance.

Note that the convention is rooted in an actual semantic meaning for
single underscore:

``from foo import *`` ignores any module global names in foo that start
with a single leading underscore.  Obviously, this has little effect for
most Python programs because you DON'T USE ``import *``.
-- 
Aahz (aahz@pythoncraft.com)           <*>         http://www.pythoncraft.com/

"....Normal is what cuts off your sixth finger and your tail..."  --Siobhan

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