Thanks. I recall installing several libraries though, where somehow
they were packaged to automatically install when opened.
In the <http://www.voidspace.org.uk/python/configobj.html>
description, I do not see much of an explanations of examples of items
like, integer(min=0, default=0). It looks like they may be called
configspecs. I see this in section 5.3.2.2.
key1 = integer(0, 30, default=15)
key2 = integer(default=15)
key3 = boolean(default=True)
key4 = option('Hello', 'Goodbye', 'Not Today', default='Not Today')
but not much else. Validators? Are there others like integer, booleand
and option? Items like start_time would then be called keywords?
Marc Tompkins wrote:
On Wed, Feb 18, 2009 at 1:01 PM, Wayne
Watson <sierra_mtnv...@sbcglobal.net>
wrote:
OK, I got the ObjectConfig
and Validate downloads, and copied your
Global class successfully. Don't I need to get the two files into
Python as a module? How does that work?
Simplest: put them in the same folder as your own program. More
standard: put them in one of the folders in your Python path - same
general idea as the DOS search path, it's a list of directories where
Python will look for modules you ask it to import.
>From the docs: ( http://docs.python.org/tutorial/modules.html)
The Module Search Path
When a module named spam is
imported, the interpreter searches for a file
named spam.py
in the current directory, and then in the list of
directories specified by the environment variable PYTHONPATH. This
has the same syntax as the shell variable PATH, that is, a
list of
directory names. When PYTHONPATH is not set, or when the file is
not
found there, the search continues in an installation-dependent default
path; on
Unix, this is usually .:/usr/local/lib/python.
Actually, modules are searched in the list of directories given by
the variable sys.path
which is initialized from the directory containing the input script
(or the current directory), PYTHONPATH and the installation- dependent
default. This allows Python programs that know what they're doing to
modify or
replace the module search path. Note that because the directory
containing the
script being run is on the search path, it is important that the script
not have
the same name as a standard module, or Python will attempt to load the
script as
a module when that module is imported. This will generally be an error.
See
section Standard
Modules for more information.
Marc Tompkins wrote:
On Wed, Feb 18, 2009 at 7:30 AM, Wayne
Watson <sierra_mtnv...@sbcglobal.net>
wrote:
See Subject. I've run
across
a 58 page document <http://www.voidspace.org.uk/python/configobj.html>,
but am
uncertain of its applicability to my present needs (see my thread on
"Changing the Attribute"). Usually, I end up with some 3-4 page
document, so this raises an eyebrow. Am I on the right trail? In the
meantime, I think I'll turn it into a more manageable pdf file before
putting it to paper.
It's a very powerful module - does lots of things you don't need yet,
and maybe never will - and I agree that it could benefit from a
hit-the-ground-running guide...
Here's a quick-and-dirty; you can flesh out the details from the
documentation you downloaded. (By the way, you'll also want to use the
validate module - another 14 pages or so...)
======================================================
* Download configobj.py and validate.py; put them somewhere in your
Python path (or in the same folder as your project, if you want)
* Add two lines to the top of your program:
from configobj import ConfigObj
from validate import Validator
* To make working with your spec easier,
import StringIO # allows you to work with strings as if they
were files
# You could just create a spec file, and open it normally, but
this keeps everything in one place.
* Somewhere in your program, create your spec and load it. There
are a lot of ways you can do this - for me, the simple thing is to put
it in a class. I create a class called Global - it's a crutch, I
know...
class Global(object):
cfgFileName = os.getcwd() + os.sep + 'Initial.sen' #
current directory + "\" + filename - but you could put it anywhere and
call it anything
# create your spec as a multi-line string between triple
quotes
tmpStr = """
mask_file_name = string(default=None)
gray_scale = boolean(default=True)
post_event_stack = boolean(default=False)
post_event_format = string(default="Tiff 2")
show_real_time = boolean(default=False)
hourly_rate = integer(min=0, default=0)
slowdown= integer(min=0, max=10, default=1) # I don't know
what this value is/does, so this is probably wrong
start_time = string(default="00:00:00") # or you could make
the default None?
stop_time = string(default="00:00:00")
lat = float(min=0.0, max=90.0) # I have no idea what you'd
want as a default latitude, if any...
"""
cfgSpec = StringIO.StringIO(tmpStr) # turns the above
string into a file-like object, which ConfigObj is expecting
cfgFile = ConfigObj(cfgFileName,
configspec=cfgSpec, raise_errors=True,
write_empty_values=True,
create_empty=True, indent_type=' ',
list_values=True) # creates the actual ConfigObj object
vtor = Validator() # creates a validator to match your
config data against your spec
* Invoke the above code when your program starts - I do it just
before my mainloop, like so:
def main(argv=None):
if argv is None:
argv = sys.argv
test = Global.cfgFile.validate(Global.vtor, copy=True) #
tries to load cfgFile; if it doesn't exist, creates it; fills in
defaults for any missing values
Global.cfgFile.write() # saves the validated file (you
don't need to do this here at the start, but I usually do)
app = MyApp(0)
app.MainLoop()
if __name__ == '__main__':
main()
* Your ConfigObj is ready to use! Simply access the contents like
a regular dictionary. To save back to the file, call the write()
method.
Global.cfgFile['mask_file_name'] = 'bogus.txt'
Global.cfgFile.write()
maskFile = Global.cfgFile['mask_file_name']
* Or use the values directly without copying to intermediate
variables:
with open(Global.cfgFile['mask_file_name'], 'w+b') as maskFile:
maskFile.write('some bogus text')
======================================================
I'm attaching that as a text file too - I suspect that my indentation
won't survive the trip...
My Global class is an ugly hack. I'm sure you'll come up with
something more aesthetically pleasing...
ConfigObj has lots of very cool features - sections, repeated sections,
custom input validators - that's what the 50+ pages of documentation
are about. When you need that stuff, it's available.
--
www.fsrtechnologies.com
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
--
Wayne Watson (Watson Adventures, Prop., Nevada City, CA)
(121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time)
"Nature, to be commanded, must be obeyed."
-- Sir Francis Bacon
Web Page: <www.speckledwithstars.net/>
--
www.fsrtechnologies.com
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
--
Wayne Watson (Watson Adventures, Prop., Nevada City, CA)
(121.01 Deg. W, 39.26 Deg. N) GMT-8 hr std. time)
"Nature, to be commanded, must be obeyed."
-- Sir Francis Bacon
Web Page: <www.speckledwithstars.net/>
|
