command line reports

[Darren Dale]

Is there a module somewhere that intelligently deals with reports to the
command line? I would like to report the progress of some pretty lengthy
simulations, and currently I have the new reports written on a new line
rather rather than overwriting the previous report.

Thanks,
Darren

[Michael Hoffman]

Darren Dale wrote:

Is there a module somewhere that intelligently deals with reports to the
command line? I would like to report the progress of some pretty lengthy
simulations, and currently I have the new reports written on a new line
rather rather than overwriting the previous report.

I'm afraid I don't understand this. Could you please give an example?

Of course, this is c.l.p., so I'm sure *someone* will understand it.
--
Michael Hoffman

[Peter Hansen]

Darren Dale wrote:

Is there a module somewhere that intelligently deals with reports to the
command line? I would like to report the progress of some pretty lengthy
simulations, and currently I have the new reports written on a new line
rather rather than overwriting the previous report.

You mean you want sys.stdout.write(report + '\r') instead of "print
report" ?

It's not really clear what you want. What's a "report" to you?

-Peter

[Darren Dale]

Peter Hansen wrote:

Darren Dale wrote:

Is there a module somewhere that intelligently deals with reports to the
command line? I would like to report the progress of some pretty lengthy
simulations, and currently I have the new reports written on a new line
rather rather than overwriting the previous report.

You mean you want sys.stdout.write(report + '\r') instead of "print
report" ?

It's not really clear what you want. What's a "report" to you?

-Peter

I am printing something like

trial 1 of 100
trial 2 of 100
....

so I get 100 lines by the time the code is finished. I would like to replace
the previous report with the current one, so I only use one line by the
time the code is finished.

I was also hoping that there was a set of tools out there for spinners,
meters, etc...

[Bengt Richter]

On Thu, 11 Aug 2005 15:43:23 -0400, Darren Dale <dd**@cornell.edu> wrote:

Peter Hansen wrote:

Darren Dale wrote:

Is there a module somewhere that intelligently deals with reports to the
command line? I would like to report the progress of some pretty lengthy
simulations, and currently I have the new reports written on a new line
rather rather than overwriting the previous report.
You mean you want sys.stdout.write(report + '\r') instead of "print
report" ?

It's not really clear what you want. What's a "report" to you?

-Peter

I am printing something like

trial 1 of 100
trial 2 of 100
...

Peter's suggestion will work, but it's easy to get something like

import sys, time
def test(): ... for i in xrange(5):
... sys.stdout.write(('trial %s of 5'%(i+1)) + '\r')
... time.sleep(.25)
... print "We're done!"
... test()

We're done!5
^--(note leftover from last "report: line)
By the same token (more or less ;-) if your "report" line shortens
during progress (e.g., changing from

'long_name_test trial 100 of 100'

to

'short_name trial 1 of 10'

you will likely see

'short_name trial n of 10 of 100'

for a while, unless you pad the report line with blanks to a constant length.

Also, I guess some platforms could require flushing stdout to be sure of
seeing the latest line as you go.

so I get 100 lines by the time the code is finished. I would like to replace
the previous report with the current one, so I only use one line by the
time the code is finished.

I was also hoping that there was a set of tools out there for spinners,
meters, etc...

The question with python for this kind of thing is usually, "Which will be
faster, googling for it, or writing it?" ;-)

Regards,
Bengt Richter

[Darren Dale]

Bengt Richter wrote:

On Thu, 11 Aug 2005 15:43:23 -0400, Darren Dale <dd**@cornell.edu> wrote:

Peter Hansen wrote:

Darren Dale wrote:
Is there a module somewhere that intelligently deals with reports to
the command line? I would like to report the progress of some pretty
lengthy simulations, and currently I have the new reports written on a
new line rather rather than overwriting the previous report.

You mean you want sys.stdout.write(report + '\r') instead of "print
report" ?

It's not really clear what you want. What's a "report" to you?

-Peter

I am printing something like

trial 1 of 100
trial 2 of 100
...

Peter's suggestion will work, but it's easy to get something like

>>> import sys, time
>>> def test(): ... for i in xrange(5):
... sys.stdout.write(('trial %s of 5'%(i+1)) + '\r')
... time.sleep(.25)
... print "We're done!"
... >>> test()

We're done!

Thanks, I didnt realize that \r is different from \n.

[Peter Hansen]

Darren Dale wrote:

Thanks, I didnt realize that \r is different from \n.

\r has is a byte with value 13, which is the Carriage Return (CR)
control character in ASCII. \n has value 10 and is the Line Feed (LF)
character. CR is named after the old teletypewriter operation involving
moving the "carriage" back to one edge to restart typing text. It
wasn't very useful without also moving to a new line (unless you wanted
to cut your paper by repeatedly printing a line of hyphens), which is
what LF was used for -- like rotating the platen (I think that's the
word) on a typewriter up one line. Hitting the arm on a typewriter is
like a CR plus a LF together, and this is immortalized in the CR/LF
combination required still under Microsoft's most advanced operating
systems, long after it's no longer necessary to have the two distinct
characters. (<sigh>)

Most operating systems have adopted the combined behaviour (go to start
of line, move down one line) together under the LF character, since
ASCII doesn't have a single "new line" character (though VT or Vertical
Tab has been proposed for that since it has no other practical use these
days). The CR character still generally does the "go to start of line"
operation when used in the console, so it's pretty handy to "overwrite
the previous line" as you wanted to. In rare situations, such as
terminal software like Hyperterm, LF doesn't necessarily take you back
to the start of a line but merely moves you down a single line at the
same column position, much like its original/intended behaviour.

-waxing-historically-and-97-percent-accurately y'rs,
Peter