[Tutor] Reading & printing lines from two different files

[Scot W. Stevenson]

Hi there,=20

Danny Yoo wrote:

> (If the files are actually much longer, we might not need to abandon
> this appraoch: we can use a variation of the zip() function by using
> Python 2.2 generators that's less of a memory hog.)

Would this be something like:

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D

from __future__ import generators

file_one =3D 'text1.txt'
file_two =3D 'text2.txt'

def generate_line(filename):
    thisfile =3D open(filename, 'r')
    for line in thisfile:
        yield line

gen_one =3D generate_line(file_one)
gen_two =3D generate_line(file_two)

while 1:
    try:
        print gen_one.next()
        print gen_two.next()
    except StopIteration:
        break

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D

This does work here, tho it seems like an awful lot of code compared with=
=20
your zip-and-readlines combination. Is there any simple way to explain wh=
y=20
this is not such a memory hog?

One thing I'm not sure of in the example above is where to put the=20
thisfile.close() line to close those files again. My computer doesn't see=
m=20
any worse for not closing them, but it does seem like bad manners...

Y, Scot


--=20
  Scot W. Stevenson -- scot@possum.in-berlin.de -- Zepernick, Germany