for loop: weird behavior

[Terry Reedy]

On 5/4/2012 4:33 PM, ferreirafm wrote:
> Hi there,
> I simply can't print anything in the second for-loop bellow:
>
> #########################################
> #!/usr/bin/env python
>
> import sys
>
> filename = sys.argv[1]
> outname = filename.split('.')[0] + '_pdr.dat'
> begin = 'Distance distribution'
> end = 'Reciprocal'
> first = 0
> last = 0
> with open(filename) as inf:
>      for num, line in enumerate(inf, 1):
>          #print num, line
>          if begin in line:
>              first = num
>          if end in line:
>              last = num

The file pointer is now at the end of the file. As an iterator, the file 
is exhausted. To reiterate, return the file pointer to the beginning 
with inf.seek(0).

>      for num, line in enumerate(inf, 1):
>          print 'Ok!'
>          print num, line
>          if num in range(first + 5, last - 1):
>              print line
>      print first, last
>      print range(first + 5, last - 1)

-- 
Terry Jan Reedy