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Re: repeat items in a list

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From Cameron Simpson <cs@zip.com.au>
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Subject Re: repeat items in a list
Date Sun, 27 Mar 2016 10:05:47 +1100
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On 26Mar2016 15:12, beliavsky@aol.com <beliavsky@aol.com> wrote:
>I can create a list that has repeated elements of another list as follows:
>
>xx = ["a","b"]
>nrep = 3
>print xx
>yy = []
>for aa in xx:
>    for i in range(nrep):
>        yy.append(aa)
>print yy
>
>output:
>['a', 'b']
>['a', 'a', 'a', 'b', 'b', 'b']
>
>Is there a one-liner to create a list with repeated elements?

Sure. As with all one liners, there comes a degree of complexity when it gets 
in the way of readability; you must decide what is better in your use case.

Look up the chain() function from the itertools module. Generate 2 (or nrep) 
length lists from each element of the original list and chain() them together.  
That gets you an iterable of all the elements. If you really need a list out 
the end instead of the iterable of the elements, convert the iterable to a list 
(hint: lists can be initialised with iterables).

Cheers,
Cameron Simpson <cs@zip.com.au>

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Thread

repeat items in a list beliavsky@aol.com - 2016-03-26 15:12 -0700
  Re: repeat items in a list Cameron Simpson <cs@zip.com.au> - 2016-03-27 10:05 +1100
  Re: repeat items in a list Erik <python@lucidity.plus.com> - 2016-03-26 23:23 +0000
    Re: repeat items in a list beliavsky@aol.com - 2016-03-26 16:36 -0700
      Re: repeat items in a list Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2016-03-28 17:30 +0000
        Re: repeat items in a list Chris Angelico <rosuav@gmail.com> - 2016-03-29 08:25 +1100
          Re: repeat items in a list Antonio Caminero Garcia <tonycamgar@gmail.com> - 2016-03-29 01:43 -0700
        Re: repeat items in a list Erik <python@lucidity.plus.com> - 2016-03-28 23:14 +0100
  Re: repeat items in a list Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-03-26 23:28 +0000
    Re: repeat items in a list beliavsky@aol.com - 2016-03-26 16:54 -0700
      Re: repeat items in a list Paul Rubin <no.email@nospam.invalid> - 2016-03-26 22:35 -0700
  Re: repeat items in a list Antonio Caminero Garcia <tonycamgar@gmail.com> - 2016-03-27 01:02 -0700
    Re: repeat items in a list Antonio Caminero Garcia <tonycamgar@gmail.com> - 2016-03-27 01:30 -0700
    Re: repeat items in a list Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-03-27 14:09 +0300
  Re: repeat items in a list larudwer <larudwer@freenet.de> - 2016-03-27 11:52 +0200
    Re: repeat items in a list Antonio Caminero Garcia <tonycamgar@gmail.com> - 2016-03-27 04:13 -0700
      Re: repeat items in a list larudwer <larudwer@freenet.de> - 2016-03-28 13:36 +0200
        Re: repeat items in a list Random832 <random832@fastmail.com> - 2016-03-28 10:04 -0400
        Re: repeat items in a list Vito De Tullio <vito.detullio@gmail.com> - 2016-03-29 23:25 +0200
        Re: repeat items in a list Michael Selik <michael.selik@gmail.com> - 2016-03-29 22:05 +0000
        Re: repeat items in a list Peter Otten <__peter__@web.de> - 2016-03-30 17:52 +0200

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