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Re: Rule of order for dot operators?

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C.D. Reimer wrote:
^^^^
Who?

> Noobie

What?

> question regarding a single line of code that transforms a URL
> slug ("this-is-a-slug") into a title ("This Is A Slug").
> 
> title = slug.replace('-',' ').title()
> 
> This line also works if I switched the dot operators around.
> 
> title = slug.title().replace('-',' ')
> 
> I'm reading the first example as character replacement first and title
> capitalization second, and the second example as title capitalization
> first and character replacement second.

You are reading correctly.

> Does python perform the dot operators from left to right or according to
> a rule of order (i.e., multiplication/division before add/subtract)?

Yes.  If you debug the code, which you should have done before posting [1] , 
you will see that

  'this-is-a-slug'.title() == 'This-Is-A-Slug'

It follows that in this special case it does not matter if you call .title() 
before or after .replace().

However, for greater efficiency, in general you should call .replace() in 
such a way that the length of the string it operates on is minimized.  For 
example, if feasible, always slice *before* .replace().

[1] <http://www.catb.org/~esr/faqs/smart-questions.html>
 
-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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Thread

Rule of order for dot operators? "C.D. Reimer" <chris@cdreimer.com> - 2015-05-16 12:20 -0700
  Re: Rule of order for dot operators? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-05-16 21:40 +0200
    Re: Rule of order for dot operators? "C.D. Reimer" <chris@cdreimer.com> - 2015-05-16 12:55 -0700
      Re: Rule of order for dot operators? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-05-17 19:17 +0200
        Re: Rule of order for dot operators? Ned Batchelder <ned@nedbatchelder.com> - 2015-05-17 10:30 -0700
          Re: Rule of order for dot operators? Rustom Mody <rustompmody@gmail.com> - 2015-05-17 12:13 -0700
        Re: Rule of order for dot operators? "C.D. Reimer" <chris@cdreimer.com> - 2015-05-17 11:35 -0700
    Re: Rule of order for dot operators? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-17 11:45 +1000
      Re: Rule of order for dot operators? Rustom Mody <rustompmody@gmail.com> - 2015-05-16 22:06 -0700
      Re: Rule of order for dot operators? Denis McMahon <denismfmcmahon@gmail.com> - 2015-05-17 15:43 +0000
        Re: Rule of order for dot operators? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-05-20 00:30 +0200
          Re: Rule of order for dot operators? Ned Batchelder <ned@nedbatchelder.com> - 2015-05-19 18:36 -0700
            Re: Rule of order for dot operators? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-05-20 04:24 +0200
              Re: Rule of order for dot operators? Ned Batchelder <ned@nedbatchelder.com> - 2015-05-19 19:44 -0700
              Re: Rule of order for dot operators? Chris Angelico <rosuav@gmail.com> - 2015-05-20 13:11 +1000
              Re: Rule of order for dot operators? Ben Finney <ben+python@benfinney.id.au> - 2015-05-20 17:29 +1000
            Re: Rule of order for dot operators? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-20 12:31 +1000
      Re: Rule of order for dot operators? "C.D. Reimer" <chris@cdreimer.com> - 2015-05-17 10:50 -0700
      Re: Rule of order for dot operators? Chris Angelico <rosuav@gmail.com> - 2015-05-18 17:40 +1000
  Re: Rule of order for dot operators? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-17 11:31 +1000
  Re: Rule of order for dot operators? Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2015-05-18 14:00 +0200

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