Newby Question for reading a file
steven.oldner at gmail.com
Thu Feb 19 21:10:22 CET 2009
On Feb 19, 1:44 pm, Curt Hash <curt.h... at gmail.com> wrote:
> On Thu, Feb 19, 2009 at 12:07 PM, steven.oldner <steven.old... at gmail.com> wrote:
> > On Feb 19, 12:40 pm, Mike Driscoll <kyoso... at gmail.com> wrote:
> > > On Feb 19, 12:32 pm, "steven.oldner" <steven.old... at gmail.com> wrote:
> > > > Simple question but I haven't found an answer. I program in ABAP, and
> > > > in ABAP you define the data structure of the file and move the file
> > > > line into the structure, and then do something to the fields. That's
> > > > my mental reference.
> > > > How do I separate or address each field in the file line with PYTHON?
> > > > What's the correct way of thinking?
> > > > Thanks!
> > > I don't really follow what you mean since I've never used ABAP, but
> > > here's how I typically read a file in Python:
> > > f = open("someFile.txt")
> > > for line in f:
> > > # do something with the line
> > > print line
> > > f.close()
> > > Of course, you can read just portions of the file too, using something
> > > like this:
> > > f.read(64)
> > > Which will read 64 bytes. For more info, check the following out:
> > >http://www.diveintopython.org/file_handling/file_objects.html
> > > - Mike
> > Hi Mike,
> > ABAP is loosely based on COBOL.
> > Here is what I was trying to do, but ended up just coding in ABAP.
> > Read a 4 column text file of about 1,000 lines and compare the 2
> > middle field of each line. If there is a difference, output the line.
> > The line's definition in ABAP is PERNR(8) type c, ENDDA(10) type c,
> > BEGDA(10) type c, and LGART(4) type c.
> > In ABAP the code is:
> > LOOP AT in_file.
> > IF in_file-endda <> in_file-begda.
> > WRITE:\ in_file. " that's same as python's print
> > ENDIF.
> > ENDLOOP.
> > I can read the file, but didn't know how to look st the fields in the
> > line. From what you wrote, I need to read each segment/field of the
> > line?
> > Thanks,
> > Steve
> > --
> You could do something like this:
> f = open('file.txt', 'r')
> for line in f:
> a,b = line.split()[1:-1] # tokenize the string into sequence of
> length 4 and store two middle values in a and b
> if a != b:
> print line
> f.close()- Hide quoted text -
> - Show quoted text -
Peter, you are correct, just fields glued together. I did not know
there was a struc module and that code looks real good. This is
something I will use in the future. Thanks!
Curt, that looks good also. I just need to test the 2 middle values.
I didn't know how to store line.split values into variables and this
is simple. Thanks!
Again, thanks Mike, Peter and Curt. Now if you ever need to know
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