At least with Python there's only one obvious way to do something :-)
I'll see your simplification and raise (or lower) you a line.
Why not simply:
for item in file('hosts.txt'):
tn = telnetlib.Telnet(item.strip())
Jeff
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Kent Johnson
Sent: Wednesday, May 10, 2006 5:52 AM
Cc: tutor@python.org
Subject: Re: [Tutor] For loop question
w chun wrote:
> another thing is that if the host file is large, you may wish to
> iterate through the file one line at a time with a list comprehension
> to do the stripping for you:
>
> HostFile = open("hosts.txt", 'r')
> for item in [x.strip() for x in HostFile]:
> :
Why is this better when the file is large? It still creates a list with
all lines in it.
>
> if you are using Python 2.4+, you can come up with an even better
> solution by using a generator expression that does lazier, ad hoc
> evaluation:
>
> HostFile = open("hosts.txt", 'r')
> for item in (x.strip() for x in HostFile):
> :
>
> this one will read and strip one line from the file as you process it
> while the previous solution still needs to come up with the entire
> list of stripped hosts before the for-loop can begin.
I would use this, it avoids reading the entire file at once and IMO is
clear and straightforward:
HostFile = open('hosts.txt')
for item in HostFile:
item = item.strip()
...
or even
HostFile = open('hosts.txt')
for item in HostFile:
tn = telnetlib.Telnet(item.strip())
...
Kent
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