counting lines using fileinput module

Robert robert.pena at gmail.com
Thu Feb 14 04:10:14 CET 2008


On Feb 13, 8:31 pm, 7stud <bbxx789_0... at yahoo.com> wrote:
> On Feb 13, 6:47 pm, Robert <robert.p... at gmail.com> wrote:
>
>
>
> > I would like to count lines in a file using the fileinput module and I
> > am getting an unusual output.
> > --------------------------------------------------------------------------- ---
> > #!/usr/bin/python
> > import fileinput
>
> > # cycle through files
> > for line in fileinput.input():
> >    if (fileinput.isfirstline()):
> >       if (fileinput.lineno > 1):
> >          print "%8d lines" % (fileinput.lineno()-1)
> >       print "%s" % fileinput.filename()
> > print "%8d lines" % fileinput.filelineno()
> > --------------------------------------------------------------------------- ------
>
> > This works fine except it prints "0 lines" first.
> > Can anyone help me understand why that is?
>
> if '<function lineno at 0x57e70>' > 1:
>     print 'yes'
>
> --output:--
> yes
>
> fileinput.lineno  v. fileinput.lineno()
>
> Whenever you have strange problems like that, insert a bunch of print
> statements to verify that the values are what you think they should
> be:
>
> for line in fileinput.input():
>     print line  #<-------*****
>     if (fileinput.isfirstline()):
>         print fileinput.lineno  #<-------*****
>         if (fileinput.lineno > 1):
>              print "%8d lines" % (fileinput.lineno()-1)
>         print "%s" % fileinput.filename()
> print "%8d lines" % fileinput.filelineno()

Thanks for the heads up. I hate it when that happens. Anyway, here is
the modified code:
-------------------------------------------------------
#!/usr/bin/python
import fileinput

file = ''
count = 0
# cycle through files
for line in fileinput.input():
   if (fileinput.isfirstline()):
      if (fileinput.lineno() > 1):
         print "%20s has %8d lines" % (file, fileinput.lineno()-1)
      file = fileinput.filename()
      count = fileinput.lineno()-1   # needed this in case there is an
empty file at the end of list
print "%20s has %8d lines" % (file, fileinput.lineno()-count)  # this
is for the last file
--------------------------------------------------------
I added count to keep track of the next to last file in the command
line list. The fileinput module opens then closes an empty file. If
there is a cleaner way to do something like this I would interested to
know. Thanks.



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