perl to python

[Olivier Scalbert]

Hello ,

What is the python way of doing this :
perl -pi -e 's/string1/string2/' file
?
Thanks
Olivier

[Kirk Job-Sluder]

On 2004-05-12, Aahz <aa**@pythoncraft.com> wrote:

In article <sl******************@eyegor.jobsluder.net>,
Kirk Job-Sluder <ki**@eyegor.jobsluder.net> wrote:

And here is the fundamental question. Why should I spend my time
writing a module in python to emulate another tool, when I can simply
use that other tool? Why should I, as a resarcher who must process
large quantities of data, spend my time and my employer's money
reinventing the wheel?

Why should your employer pay for the time for all of its employees to
learn all of those other tools, when Python will do the job?

As was brought up earlier. Creating custom python scripts to reinvent
the wheel is also loaded with training costs. I would argue the
following:

1: Using an existing idiomatic tool takes advantage of standardization.
"perl -pi -e" exhibits the same behavior on multiple platforms and even
different versions of perl. It is an idiomatic expression that is very
well documented, and for which 100s of examples through a quick google
search.

2: Memorizing two lines is more difficult than memorizing one line.

3: The alternative proposal, writing a site-specific module is even
worse when it comes to training requirements.

Or to turn this around, why should anybody learn to use tar, find, less,
rsync or diff when you can do the same thing in python?

[Josh Gilbert]

It's in the python man page:

-u Force stdin, stdout and stderr to be totally unbuffered.
On systems where it matters, also put stdin, stdout and stderr in binary
mode. Note that there is internal buffering in xread-lines(),
readlines() and file-object iterators ("for line in sys.stdin") which
is not influenced by this option. To work around this, you will want to
use "sys.stdin.readline()" inside a "while 1:" loop.

When I use sys.stdin.readline I don't need to use to -u flag.

You can also use raw_input() to get data from stdin. This also appears to
strip out the newline.
Josh Gilbert.

Andrew Dalke wrote:

Scott Schwartz

No effect, because that's not the problem.

Ahh, you're right. I keyword matched "buffer" and thought you meant
the system buffer and not Python's.

Andrew
da***@dalkescientific.com

[Russell Wallace]

On Tue, 11 May 2004 14:45:59 +0100, Peter Hickman
<pe***@semantico.com> wrote:

There is more to computer usage than sysadmin tasks, sed is an ideal
tool for processing large sets of large files (I have to handle small
files that are only 130 Mb in size, and I have around 140,000 of them).

Out of curiosity, what are you doing that generates 140,000 files of
130 megabytes each?

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