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Re: What use for reversed()?

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On Sun, 31 May 2015 12:40:19 -0700, fl wrote:

> Hi,
> 
> I have a string b='1234'. I run: br=reversed(b)
> 
> I hope that I can print out '4321' by:
> 
> for br in b
> 
> but it complains:
> SyntaxError: invalid syntax
> 
> 
> My questions:
> 1. What use for reversed(). I do not find an example on web.
> 
> 2. If reversed() is wrong the my purpose, what method can do it? i.e.
> '4321'
> out.

reversed returns an iterator, not a list, so it returns the reversed list 
of elements one at a time. You can use list() or create a list from 
reversed and then join the result:

$ python
Python 2.7.3 (default, Dec 18 2014, 19:10:20) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> "".join(list(reversed("fred")))
'derf'
>>> "".join([x for x in reversed("fred")])
'derf'

So reversed can do it, but needs a little help

-- 
Denis McMahon, denismfmcmahon@gmail.com

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What use for reversed()? fl <rxjwg98@gmail.com> - 2015-05-31 12:40 -0700
  Re: What use for reversed()? Denis McMahon <denismfmcmahon@gmail.com> - 2015-05-31 19:58 +0000
    Re: What use for reversed()? Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-31 18:06 -0600
  Re: What use for reversed()? cheshire <supportNOSPAM@microsoft.com> - 2015-05-31 23:26 +0200
  Re: What use for reversed()? Tim Delaney <timothy.c.delaney@gmail.com> - 2015-06-01 09:23 +1000
    Re: What use for reversed()? fl <rxjwg98@gmail.com> - 2015-05-31 20:11 -0700
  Re: What use for reversed()? Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-06-01 01:30 +0100
  Re: What use for reversed()? Tim Delaney <timothy.c.delaney@gmail.com> - 2015-06-01 13:59 +1000
  Re: What use for reversed()? fl <rxjwg98@gmail.com> - 2015-05-31 22:15 -0700
    Re: What use for reversed()? Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2015-06-01 09:11 +0300

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