[Tutor] List manipulation

[Srinivas Iyyer]

Dear Kent and Bob,
thank you for your solutions. It helped, however,
based on your suggestions, I intended to solve a
chromosome walking problem. I posted my question on
subject name:
'Limitation of range() function in Walking problem'. 

Thanks again. 
Sri

--- Kent Johnson <kent37 at tds.net> wrote:

> Srinivas Iyyer wrote:
> > Thank you Bob for your email.
> > Sorry for the confusion. 
> > here is what I ment:
> > 
> > test = ['10\t15', '16\t20', '25\t35', '45\t50',
> > '55\t60', '61\t65', '75\t80']
> 
> >>> I would get:
> >>> 10      20
> >>> 25      35
> >>> 45      50
> >>> 55      65
> >>> 75      80
> 
> Here is my take on it:
> 
> test = ['10\t15', '16\t20', '25\t35',
> '45\t50','55\t60', '61\t65', '75\t80']
> 
> pairs = [ map(int, x.split('\t')) for x in test ]
> 
> i = iter(pairs)
> 
> last = i.next()
> 
> for current in i:
>      if current[0] == last[1]+1:
>          last = [last[0], current[1]]
>      else:
>          print last
>          last = current
> 
> print last
> 
> 
> You can also wrap this in a generator which yields
> the desired pairs, so 
> they can be printed or put in a list or whatever:
> 
> def compress(pairs):
>      i = iter(pairs)
> 
>      last = i.next()
> 
>      for current in i:
>          if current[0] == last[1]+1:
>              last = [last[0], current[1]]
>          else:
>              yield last
>              last = current
> 
>      yield last
> 
> 
> for pair in compress(pairs):
>      print pair
> 
> 
> Kent
> 
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> http://mail.python.org/mailman/listinfo/tutor
> 


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