Re: subprocess svn checkout password issue
On Saturday, 16 March 2019 16:50:23 UTC+11, dieter wrote:
> Martin De Kauwe writes:
>
> > I'm trying to write a script that will make a checkout from a svn repo and
> > build the result for the user. However, when I attempt to interface with
> > the shell it asks the user for their filename and I don't know how to
> > capture this with my implementation.
> >
> > user = "XXX578"
> > root="https://trac.nci.org.au/svn/cable";
> > repo_name = "CMIP6-MOSRS"
> >
> > cmd = "svn checkout %s/branches/Users/%s/%s" % (root, user, repo_name)
> > p = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
> > stdout=subprocess.PIPE,
> > stderr=subprocess.PIPE)
> > error = subprocess.call(cmd, shell=True)
> > if error is 1:
> > raise("Error downloading repo"
> >
> > I tried adding .wait(timeout=60) to the subprocess.Popen command but that
> > didn't work.
> >
> > Any advice on whether there is an augmentation to the above, or a better
> > approach, would be much appreciated. I need to solve this with standard
> > python libs as I'm trying to make this as simple as possible for the user.
>
> That is non-trivial.
>
> Read the "svn" documentation. You might be able to pass in the
> required information by other means, maybe an option, maybe
> an envvar, maybe via a configuration file.
>
> Otherwise, you must monitor what it written to the subprocess'
> "stdout" and "stderr", recognized the interaction request
> perform the interaction with the user and send the result
> to the subprocess' stdin.
Thanks, I think this solution will work.
import subprocess
import getpass
user = "XXX578"
root="https://trac.nci.org.au/svn/cable";
repo_name = "CMIP6-MOSRS"
pswd = "'" + getpass.getpass('Password:') + "'"
cmd = "svn checkout %s/branches/Users/%s/%s --password %s" %\
(root, user, repo_name, pswd)
error = subprocess.call(cmd, shell=True)
if error is 1:
raise("Error checking out repo")
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subprocess svn checkout password issue
Hi,
I'm trying to write a script that will make a checkout from a svn repo and
build the result for the user. However, when I attempt to interface with the
shell it asks the user for their filename and I don't know how to capture this
with my implementation.
user = "XXX578"
root="https://trac.nci.org.au/svn/cable";
repo_name = "CMIP6-MOSRS"
cmd = "svn checkout %s/branches/Users/%s/%s" % (root, user, repo_name)
p = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
error = subprocess.call(cmd, shell=True)
if error is 1:
raise("Error downloading repo"
I tried adding .wait(timeout=60) to the subprocess.Popen command but that
didn't work.
Any advice on whether there is an augmentation to the above, or a better
approach, would be much appreciated. I need to solve this with standard python
libs as I'm trying to make this as simple as possible for the user.
The full script is here if that helps:
https://github.com/mdekauwe/CABLE_benchmarking/blob/master/scripts/get_cable.py
Thanks
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Re: splitting numpy array unevenly
On Tuesday, September 18, 2012 8:31:09 AM UTC+10, Wanderer wrote: > I need to divide a 512x512 image array with the first horizontal and vertical > division 49 pixels in. Then every 59 pixels in after that. hsplit and vsplit > want to start at the edges and create a bunch of same size arrays. Is there a > command to chop off different sized arrays? > > > > Thanks I don't know that I follow completely, but can't you just slice what you are after? x = np.random.rand(512*512).reshape(512,512) xx = x[0,:49] And put the rest of the slices in a loop...? -- http://mail.python.org/mailman/listinfo/python-list
Re: Best way to print a module?
Trying to follow the suggestion this would be the alternate
implementation.
import sys
sys.path.append("/Users/mdekauwe/Desktop/")
import params
#params.py contains
#apples = 12.0
#cats = 14.0
#dogs = 1.3
fname = "test.asc"
try:
ofile = open(fname, 'w')
except IOError:
raise IOError("Can't open %s file for write" % fname)
attributes = [attr for attr in dir(params) if not
attr.startswith('__')]
attributes.sort()
try:
ofile.write("[params]\n")
for i in attributes:
ofile.write("%s = %s\n" % (i, getattr(params, i)))
except IOError:
raise IOError("Error writing params files, params section")
Is that a better version? I honestly don't know.
thanks
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Re: Best way to print a module?
Hi,
Tim yes I had a feeling my posting might be read as ambiguous! Sorry I
was trying to quickly think of a good example. Essentially I have a
set of .ini parameter files which I read into my program using
configobj, I then replace the default module parameters if the user
file is different (in my program). When it comes to writing the data
back out I need to potentially loop over 5 module files and I need to
ignore the superfluous information. My guess is that the way I am
doing it might be a little on the slow side, hence the posting. Like
you said it might be that the way I am doing it is "fine", I just
wanted to see if there was a better way that is all.
Rantingrick I did actually try the dir() to start with, I can't
remember why I changed back. I will try your suggestion and see
(thanks)
So instead of sys as per my example my module more realistically looks
like this:
params.py
apples = 12.0
cats = 14.0
dogs = 1.3
so my fuller example then
import sys
sys.path.append("/Users/mdekauwe/Desktop/")
import params
#params.py contains
#apples = 12.0
#cats = 14.0
#dogs = 1.3
fname = "test.asc"
try:
ofile = open(fname, 'w')
except IOError:
raise IOError("Can't open %s file for write" % fname)
data = []
for attr in params.__dict__.keys():
if not attr.startswith('__') and not attr.endswith('__'):
attr_val = getattr(params, attr)
data.append((attr, attr_val))
data.sort()
try:
ofile.write("[params]\n")
for i in data:
ofile.write("%s = %s\n" % (i[0], i[1]))
except IOError:
raise IOError("Error writing params files, params section")
etc, etc
thanks
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Best way to print a module?
Hi,
If I wanted to print an entire module, skipping the attributes
starting with "__" is there an *optimal* way? Currently I am doing
something like this. Note I am just using sys here to make the point
import sys
data = []
for attr in sys.__dict__.keys():
if not attr.startswith('__') and not attr.endswith('__'):
attr_val = getattr(sys, attr)
data.append((attr, attr_val))
data.sort()
for i in data:
print "%s = %s" % (i[0], i[1])
Clearly this would be quicker if I didn't store it and sort the
output, i.e.
for attr in sys.__dict__.keys():
if not attr.startswith('__') and not attr.endswith('__'):
attr_val = getattr(sys, attr)
print "%s = %s" % (attr, attr_val)
Anyway if there is a better way it would be useful to hear it...
Many thanks,
Martin
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Re: working with raw image files
what is a .raw file, do you mean a flat binary? -- http://mail.python.org/mailman/listinfo/python-list
Re: replace regex in file using a dictionary
yes thanks both work nicely, I will ponder the suggestions. -- http://mail.python.org/mailman/listinfo/python-list
replace regex in file using a dictionary
Hi,
So i want to replace multiple lines in a text file and I have reasoned
the best way to do this is with a dictionary. I have simplified my
example and broadly I get what I want however I am now printing my
replacement string and part of the original expression. I am guessing
that I will need to use a more complicated expression than I am
currently am to achieve what I want?
my aim is to match the expression before the "=" and replace the
string after the equals...
My failed example...
def replace_keys(text, replacements_dict):
for key, var in replacements_dict.iteritems():
replacement = "%s = %s" % (key, var)
text = text.replace(key, replacement)
return text
# example of two lines of the file
str = \
"""structcn = 150.0
metfrac0 = 0.85
"""
# replacements
replacement_dict = {"structcn": "999.0", "metfrac0": "0.85"}
new_str = replace_keys(str, replacement_dict)
print str
print
print new_str
which produces...
structcn = 150.0
metfrac0 = 0.85
structcn = 999.0 = 150.0
metfrac0 = 0.85 = 0.85
thanks.
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Re: Fun python 3.2 one-liner
what is the character limit on a one liner :P. Very interesting jesting apart, any more? -- http://mail.python.org/mailman/listinfo/python-list
Re: Bounds checking
On Mar 21, 9:43 pm, Jean-Michel Pichavant wrote: > Martin De Kauwe wrote: > >> Sorry, are you trying to say that it is not practical to write correct > >> code that isn't buggy? Well, you're honest, at least, still I can't help > >> but feel that you're admitting defeat before even starting. > > > No. What I am saying is the code is written has been well tested and > > *appears* to be working well. However the code is complicated and > > there is potential for bugs. I think I am just been practical here, > > evidently I can't think of everything, but there are some clear and > > obvious errors that would be worth checking for. I can only explain > > this in the terms of the code (sorry)...but for example the model > > estimates plant photosynthesis and then allocates the carbon. So one > > clear example is that the model cuts back carbon production if there > > is water stress for the plant. This involves "removing" carbon from > > the state. Clearly if you ended up in a situation where there is > > negative carbon in a leaf, i.e. the leaf doesn't exist well this is > > not physically possible and would be a code issue. Whilst this is > > unlikely I think it would be nice to have a catch for it. Another > > example would be the amount of soil water available to the plant, > > again there can be zero but not negative soil water. It wouldn't be > > meaningful. I hope that makes sense? > > > thanks > > Not that much. You'll spot bugs where negative numbers will be set to > some attribute but what if 42 is put instead of 43 in one of your > attribute ? Same consequence, it will mess up with your model but none > of your check will spot that error. > > Try to identify those complicated functions you mentioned, and write > unitary tests for them. Use a set of input parameters with the expected > function return value. That way you'll be able to spot errors, whether > the attribute is negative or not. > > JM > > PS : writing unitary tests takes time, a lot of time. Hi, Yes you make a good point. I think what I was trying to get across is there are certain scenarios which can't physically happen and they are straight forward to check for. I just thought it might be nice to add a check for these. However you make a good case and I definitely take your point. I guess I should look into unitary tests then (any suggestions?) ta. -- http://mail.python.org/mailman/listinfo/python-list
Re: Bounds checking
On Mar 19, 8:40 pm, Steven D'Aprano wrote: > On Sat, 19 Mar 2011 01:38:10 -0700, Martin De Kauwe wrote: > >> Why don't you do the range check *before* storing it in state? That way > >> you can identify the calculation that was wrong, instead of merely > >> noticing that at some point some unknown calculation went wrong. > > > I guess no reason really. I suppose in my mind I was thinking it was an > > unlikely safeguard but I liked the idea of adding so would just do it at > > the end of a time step. In reality I think there is practically no > > difference and this way it is done once, in a single location vs. > > potential 10 separate checks? I don't see the advantage? > > You should always aim to fail as close as possible to the source of the > error as is practical. That decreases the amount of debugging required > when something fails: instead of searching your entire program, you only > have to search a very small amount of code. > > -- > Steven OK I take your point and can see the superior logic! I shall amend what I was planning -- http://mail.python.org/mailman/listinfo/python-list
Re: Bounds checking
> Sorry, are you trying to say that it is not practical to write correct > code that isn't buggy? Well, you're honest, at least, still I can't help > but feel that you're admitting defeat before even starting. No. What I am saying is the code is written has been well tested and *appears* to be working well. However the code is complicated and there is potential for bugs. I think I am just been practical here, evidently I can't think of everything, but there are some clear and obvious errors that would be worth checking for. I can only explain this in the terms of the code (sorry)...but for example the model estimates plant photosynthesis and then allocates the carbon. So one clear example is that the model cuts back carbon production if there is water stress for the plant. This involves "removing" carbon from the state. Clearly if you ended up in a situation where there is negative carbon in a leaf, i.e. the leaf doesn't exist well this is not physically possible and would be a code issue. Whilst this is unlikely I think it would be nice to have a catch for it. Another example would be the amount of soil water available to the plant, again there can be zero but not negative soil water. It wouldn't be meaningful. I hope that makes sense? thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Bounds checking
> assert all(x >= 0 for x in (a, b, c, d, e, f, g, h, i, j)) yep neat! > Why don't you do the range check *before* storing it in state? That way > you can identify the calculation that was wrong, instead of merely > noticing that at some point some unknown calculation went wrong. I guess no reason really. I suppose in my mind I was thinking it was an unlikely safeguard but I liked the idea of adding so would just do it at the end of a time step. In reality I think there is practically no difference and this way it is done once, in a single location vs. potential 10 separate checks? I don't see the advantage? > You're looking at every single attribute, including those of super > classes, when you only want to check "10 or so" attributes. That's > probably not wise. At the very least, dir() will be a fairly expensive > call. yes your right, sorry I was just trying to post a quick example to go with my question. I would use a list of the attributes to check. > > If you insist on checking state *after* the value is stored, instead of > preventing it from being stored in the first place, it is better to make > the state object responsible for doing it's own bounds checking. That way > only the state object needs to be updated when you change those ten > attributes, instead of some arbitrary number of places scattered all > throughout your code. yes I think this is what I was getting at, I will look at your suggestion thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Bounds checking
> dir() has to do a bit a computation. I would be tempted to give 'state' > a set of attributes to check. Call it 'nonnegatives'. > for attr in nonnegatives: > if ... > > This allows for attributes not subject to that check. > > -- > Terry Jan Reedy Agreed. I was trying to just write a dummy example quickly to go with my question and that was just the way that came to mind so that I could loop over them to test. It wasn't a great example sorry! In reality I would just have like you said a subset a list I guess of the ones I would check. -- http://mail.python.org/mailman/listinfo/python-list
Re: Bounds checking
> Offhand, my only quibble is that sys.exit is not helpful for debugging.
> Much better to raise an error:
>
> if not self.funcTable.get(attribute, lambda x: True)(value):
> raise ValueError ('error out of bound')
>
> or define a subclass of ValueError just for this purpose. On error, the
> program will stop just as dead, but you'll get a trace.
>
> Mel.
I think generally I prefer my code to die and as long as I know where
(from the statement) the error occurred I know generally what point I
have to debug up until. Can you explain how your solution would be
easier with a trace as I don't tend to use the raise/assert
functionality so I am interested.
thanks
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Re: Bounds checking
> Don't check for bounds, fix any bug in the code that would set your
> values out of bounds and use asserts while debugging.
>
whilst that is a nice idea in practice this just is not a practical
solution.
> Otherwise if you really need dynamic checks, it will cost you cpu, for
> sure.
Yes I agree and I hadn't decided whether to add it or not as there
aren't any current issues. However I can see that the check would
overall be safer. I was just wondering if there was some super smartie
pants solution :P
Howeverver you could for instance override the __setatttr__ of
> state object, and call the attribute's associated function.
>
> class State(object):
> funcTable = {
> 'foo': lambda x: x >= 0.0
> }
>
> def __init__(self):
> self.foo = 0
>
> def __setattr__(self, attribute, value):
> if not self.funcTable.get(attribute, lambda x: True)(value):
> sys.exit('error out of bound')
> return object.__setattr(self, attribute, value)
>
> Untested, however it's just an idea. I'm not even sure that would be
> less cpu consuming :D
thanks I will look at what you suggested.
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Bounds checking
Hi,
if one has a set of values which should never step outside certain
bounds (for example if the values were negative then they wouldn't be
physically meaningful) is there a nice way to bounds check? I
potentially have 10 or so values I would like to check at the end of
each iteration. However as the loop is over many years I figured I
probably want to be as optimal as possible with my check. Any
thoughts?
e.g. this is my solution
# module contain data
# e.g. print state.something might produce 4.0
import state as state
def main():
for i in xrange(num_days):
# do stuff
# bounds check at end of iteration
bounds_check(state)
def bounds_check(state):
""" check state values are > 0 """
for attr in dir(state):
if not attr.startswith('__') and getattr(state, attr) < 0.0:
print "Error state values < 0: %s" % (attr)
sys.exit()
if __name__ == "__main__":
sys.exit(main())
thanks
Martin
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Code structure help
Hi, I have been working on re-writing a model in python and have been trying to adopt some of the advise offered on here to recent questions. However I am not sure how easy on the eye my final structure is and would appreciate any constructive comments/ suggestions. So broadly the model estimates plant growth using a number of related sub functions which I have grouped into classes and they all live in separate files. My main issue at the moment is I think I have a lot of verbose class instances but I really can't see a better way to do it. I have left some of the bones of the code out but this is basically what would it looks like. thanks. import constants as const from file_parser import ConfigFileParser from plant_growth import PlantGrowth from print_outputs import PrintOutput from litter import LitterFlows from decomp import DecompFactors from soil_cnflows import CarbonFlows, NitrogenFlows from nmineralisation import Mineralisation from update_pools import CarbonPools, NitrogenPools ...etc... class ModelName(object): def __init__(self, cfg_fname=None): """ Set everything up Read meterological forcing file, any user adjusted files. If there is anything in the user file then adjust the model parameters, control or initial state attributes that are used within the code. """ # sweep the cmd line options, args = cmdline_parser() # quit if asked only to dump default paramater files if options.DUMP_INPUT == True: ...call some stuff... # read in user defined variables (stored in dictionaries) pars = ConfigFileParser(cfg_fname=cfg_fname) (control, params, state, files, fluxes, met_data) = pars.main() # objects holding model state, fluxes, parameters and control flags self.met_data = met_data self.control = control self.params = params self.state = state self.fluxes = fluxes # instances of other model parts.. self.pr = PrintOutput(self.params, self.state, self.fluxes, self.control, self.files, dump=False) # start date of simulation self.date = self.simulation_start_date() ...etc def run_sim(self): mi = Mineralisation(self.control, self.params, self.state, self.fluxes) cf = CarbonFlows(self.control, self.params, self.state, self.fluxes) nf = NitrogenFlows(self.control, self.params, self.state, self.fluxes) de = Derive(self.control, self.params, self.state, self.fluxes) dc = DecompFactors(self.control, self.params, self.state, self.fluxes) lf = LitterFlows(self.control, self.params, self.state, self.fluxes) pg = PlantGrowth(self.control, self.params, self.state, self.fluxes, self.met_data) cpl = CarbonPools(self.control, self.params, self.state, self.fluxes) npl = NitrogenPools(self.control, self.params, self.state, self.fluxes) for i in self.met_data.doy: project_day = i - 1 # N:C ratios leafnc, rootnc = self.leaf_root_ncratio() # litterfall rate: C and N fluxes lf.flows(leafnc, rootnc) # plant growth pg.grow(project_day, self.date, leafnc) # calculate model decay rates dc.decay_rates() # soil model fluxes cf.calculate_cflows() nf.calculate_nflows() # N uptake and loss mi.calculate_mineralisation() # carbon sink or source? self.fluxes.nep = (self.fluxes.npp - self.fluxes.hetero_resp - self.fluxes.ceaten * (1. - self.params.fracfaeces)) # soil model - update pools cact, cslo, cpas = cpl.calculate_cpools() npl.calculate_npools(cact, cslo, cpas) if self.control.print_options == 1: self.pr.print_state() self.pr.print_fluxes() self.increment_date() if self.control.print_options == 2: self.pr.print_state() self.pr.print_fluxes() # house cleaning, close ouput files self.pr.tidy_up() -- http://mail.python.org/mailman/listinfo/python-list
Re: Defining class attributes + inheritance
On Mar 9, 12:53 pm, "Rhodri James" wrote: > On Wed, 09 Mar 2011 01:00:29 -0000, Martin De Kauwe > wrote: > > > class BaseClass(object): > > def __init__(self, a, b, c, d): > > self.a = a > > self.b = b > > self.c = c > > self.d = d > > > class NewClass(BaseClass): > > def __init__(self): > > super(NewClass, self).__init__(new) > > self.new = new > > print self.new > > Two things leap out immediately. First, BaseClass.__init__ takes four > parameters besides `self`, but when you call it you only give it one > parameter, `new`. It's not going to like that. Second, where did `new` > come from? It's not a parameter to NewClass.__init__, and it doesn't seem > to be a global. That's not going to work well either. > > However neither of these things are what the traceback is complaining > about. > > > if __name__ == "__main__": > > > A = PreviousClass(1, 2, 3, 4, 5) > > B = NewClass(1, 2, 3, 4, 5) > > > $ python test.py > > Traceback (most recent call last): > > File "model_data.py", line 29, in > > B = NewClass(1, 2, 3, 4, 5) > > TypeError: __init__() takes exactly 1 argument (6 given) > > When you create your NewClass, you give it five parameters (1, 2, 3, 4, 5) > plus the implicit `self`, which is the "(6 given)" part of the message. > However NewClass.__init__ takes no parameters aside from `self` (i.e. it > "takes exactly 1 argument"). There's a mismatch between what you've told > NewClass.__init__ to expect and what you actually deliver to it. > > The point that may be confusing you is that NewClass.__init__ knows > nothing at all about BaseClass.__init__. It doesn't inherit parameters > from it or anything magical like that; you have to tell it everything. If > you want parameters to pass from NewClass.__init__ to BaseClass.__init__ > you will have to provide them somehow. In this case, I think what you > meant was something like this: > > class NewClass(BaseClass): > def __init__(self, a, b, c, d, new): > super(NewClass, self).__init__(a, b, c, d) > self.new = new > # etc > > -- > Rhodri James *-* Wildebeest Herder to the Masses Yep that was it, I think I misunderstood and assumed it knew about stuff in the BaseClass constructor. All makes sense now! -- http://mail.python.org/mailman/listinfo/python-list
Re: Defining class attributes + inheritance
On Mar 9, 11:50 am, "Rhodri James" wrote: > On Wed, 09 Mar 2011 00:29:18 -0000, Martin De Kauwe > wrote: > > > > > > > > > On Mar 9, 10:20 am, Ethan Furman wrote: > [snip] > >> Just make sure and call the parent's constructor, either with > > >> class NewClass(BaseClass): > >> def __init__(self, ): > >> BaseClass.__init__(self, other_params) > > >> or > > >> class NewClass(BaseClass): > >> def __init__(self, ): > >> super(NewClass, self).__init__() > > >> ~Ethan~ > > > Hi thanks, but I think I am implementing it wrong then? > > > BaseClass has 4 attributes and when I tried what you said > > > class NewClass(BaseClass): > > def __init__(self): > > super(NewClass, self).__init__(new_thing) > > > I get the error > > > TypeError: __init__() takes exactly 1 argument (6 given) > > Please give us either the rest of the code or the rest of the > traceback, or preferably both. Without one or the other we have > little hope of guessing what you've typed. > > -- > Rhodri James *-* Wildebeest Herder to the Masses OK class BaseClass(object): def __init__(self, a, b, c, d): self.a = a self.b = b self.c = c self.d = d class NewClass(BaseClass): def __init__(self): super(NewClass, self).__init__(new) self.new = new print self.new class PreviousClass: def __init__(self, a, b, c, d, new): self.a = a self.b = b self.c = c self.d = d self.new = new print self.new if __name__ == "__main__": A = PreviousClass(1, 2, 3, 4, 5) B = NewClass(1, 2, 3, 4, 5) $ python test.py Traceback (most recent call last): File "model_data.py", line 29, in B = NewClass(1, 2, 3, 4, 5) TypeError: __init__() takes exactly 1 argument (6 given) So NewClass is my attempt to implement what I was shown and PreviousClass was how I was originally solving the issue, i.e. I wouldn't inherit the BaseClass. thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Defining class attributes + inheritance
On Mar 9, 10:20 am, Ethan Furman wrote: > Martin De Kauwe wrote: > > Hi, > > > I think this might be obvious? I have a base class which contains X > > objects which other classes inherit e.g. > > > class BaseClass(object): > > def __init__(self, something, something_else): > > self.something = something > > self.something_else = something_else > > # etc > > > Typically I would use this like this > > > from some_module_name import BaseClass > > > class NewClass(BaseClass): > > def do_something(self): > > print self.something > > # etc > > > Which is fine. However if I need to inherit additional attributes (to > > NewClass) at the constructor step it means I have to completely > > redefine the constructor [...] > > Just make sure and call the parent's constructor, either with > > class NewClass(BaseClass): > def __init__(self, ): > BaseClass.__init__(self, other_params) > > or > > class NewClass(BaseClass): > def __init__(self, ): > super(NewClass, self).__init__() > > ~Ethan~ Hi thanks, but I think I am implementing it wrong then? BaseClass has 4 attributes and when I tried what you said class NewClass(BaseClass): def __init__(self): super(NewClass, self).__init__(new_thing) I get the error TypeError: __init__() takes exactly 1 argument (6 given) -- http://mail.python.org/mailman/listinfo/python-list
Defining class attributes + inheritance
Hi, I think this might be obvious? I have a base class which contains X objects which other classes inherit e.g. class BaseClass(object): def __init__(self, something, something_else): self.something = something self.something_else = something_else # etc Typically I would use this like this from some_module_name import BaseClass class NewClass(BaseClass): def do_something(self): print self.something # etc Which is fine. However if I need to inherit additional attributes (to NewClass) at the constructor step it means I have to completely redefine the constructor and therefore can't inherit in this way, which defeats the purpose of defining a default base class. Am I being slow is there a nice solution to this or is that the way it works? thanks, Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: OT: Code Examples
On Mar 2, 3:30 am, Robert Kern wrote: > On 2/28/11 10:03 AM, Fred Marshall wrote: > > > I'm interested in developing Python-based programs, including an engineering > > app. ... re-writing from Fortran and C versions. One of the objectives > > would to > > be make reasonable use of the available structure (objects, etc.). So, I'd > > like > > to read a couple of good, simple scientific-oriented programs that do that > > kind > > of thing. > > You may want to take a look at Clear Climate Code. It is a rewrite of an old, > hairy FORTRAN climate analysis program with the goal of making it clearer and > easier to understand. That's somewhat different from having an example of what > you would write de novo, but it might help give you strategies for the process > of translating your own FORTRAN and C engineering codes. > > http://clearclimatecode.org/ > > -- > Robert Kern > > "I have come to believe that the whole world is an enigma, a harmless enigma > that is made terrible by our own mad attempt to interpret it as though it > had > an underlying truth." > -- Umberto Eco that link is really useful helps that it is the same field! Does anyone have any more like that? -- http://mail.python.org/mailman/listinfo/python-list
Re: OT: Code Examples
On Mar 1, 3:03 am, Fred Marshall wrote: > I'm interested in developing Python-based programs, including an > engineering app. ... re-writing from Fortran and C versions. One of the > objectives would to be make reasonable use of the available structure > (objects, etc.). So, I'd like to read a couple of good, simple > scientific-oriented programs that do that kind of thing. > > Looking for links, etc. > > Fred you could try searching here http://pypi.python.org/pypi. I had a look for models, but didn't find anything in particular. But would be really useful if anyone does know of some good examples -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
I managed to get it to work like it explained, apologies not sure what I did wrong earlier, odd. Anyway thanks a lot for all of the suggestions + help -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 14, 8:57 pm, Martin De Kauwe wrote: > On Feb 14, 8:51 pm, Dave Angel wrote: > > > > > > > On 01/-10/-28163 02:59 PM, Martin De Kauwe wrote: > > > > > > > > from other_model import OtherSubModel > > > class Model: > > > > def __init__(self): > > > > # included other external modules (i.e. in other files) > > > om =therSubModel() > > > > def run(self): > > > # call other submodel and pass params > > > om.run(params) > > > What's om supposed to be? You define a local variable in one method, > > and try to use it in a different one > > > Perhaps you meant self.om = > > > > class OtherSubModel: > > > def __init__(self): > > > #some stuff > > > > > > def run(params): > > > You're missing a self here in the formal parameter list. > > > DaveA > > I was trying to write a smaller version of broadly what I think i am > doing, perhaps I am not implementing it correctly. I have one model > which I have coded as a class, there were a few parts which could be > used separately (sub-models). So I decided to make them separate > classes in separate files which I *thought* I could just join up into > one package at run time. This way I could also use these modules > separately. > > So in the dummy example > > the other file is imported > > from other_model import OtherSubModel > > amd om = OtherSubModel was me making an instance of it? And then when > I called the *run* part of this sub-model I was passing it the > parameter file. I am sensing I have this wrong? oh and yes i did mean self.om.run(params), sorry! -- http://mail.python.org/mailman/listinfo/python-list
Re: How to create a dict based on such a file?
On Feb 14, 6:10 pm, aspineux wrote:
> On 14 fév, 06:47, Wang Coeus wrote:
>
> > Hi all,
> > I am new to python. Currently I encountered a problem, please help me to
> > solve this. Thanks in advance!
> > I have a file like below:
>
> ConfigParser Library does exacly what you want but with .ini file
> format
> [block1]
> key1=value1
> key2=value2
> ...
>
> Can you change the format of your file ? If so
>
> import ConfigParser
> config=ConfigParser.RawConfigParser(config_default)
> try:
> config.readfp(open(filename, 'r'))
> except Exception, e:
> logging.error('error reading configuration file %s: %s', filename,
> e)
> sys.exit(1)
>
> def func(config, key1):
> result={}
> for section in config.sections():
> if config.has_option(section, key1):
> result[section]=config.get(section, key1)
> return result
>
> If not, you need to parse youre file, and the some question :
> How or what generate this file, is it always the same format ? Could
> it chnage, for exemple for
>
> block1 { key1=value1 key2=value2 }
>
> or at least
>
> block1 {
>
> key1=value1
> key2=value2
>
> }
>
> Is-it big, too big to keep in memory ?
>
>
>
> > ++
> > block1
> > {
> > key1=value1
> > key2=value2
> > key3=value3}
>
> > block2
> > {
> > key1=value4
> > key2=value5
> > key4=value6}
>
> > ...
> > blockn
> > {
> > key1=value7
> > key2=value8
> > keyn=valuen}
>
> > +++
> > Different block may have different keys and even same key in different
> > blocks may have different values.
>
> > Now I want to get a function, which like this:
> > func(key)
> > and it will return a dictionary as below:
> > func(key1) = [block1:value1,block2:value4,...,blockn:value7]
> > and if one block has no "key1" parameter, it will not include in this
> > dict.
>
> > Thanks a lot!
> > --
> > Coeus
> > In the middle of every difficulty lies opportunity.
> > -- Albert Einstein
configobj is even better, very similar usage.
--
http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 14, 8:51 pm, Dave Angel wrote: > On 01/-10/-28163 02:59 PM, Martin De Kauwe wrote: > > > > > > from other_model import OtherSubModel > > class Model: > > > def __init__(self): > > > # included other external modules (i.e. in other files) > > om =therSubModel() > > > def run(self): > > # call other submodel and pass params > > om.run(params) > > What's om supposed to be? You define a local variable in one method, > and try to use it in a different one > > Perhaps you meant self.om = > > > class OtherSubModel: > > def __init__(self): > > #some stuff > > > > def run(params): > > You're missing a self here in the formal parameter list. > > DaveA I was trying to write a smaller version of broadly what I think i am doing, perhaps I am not implementing it correctly. I have one model which I have coded as a class, there were a few parts which could be used separately (sub-models). So I decided to make them separate classes in separate files which I *thought* I could just join up into one package at run time. This way I could also use these modules separately. So in the dummy example the other file is imported from other_model import OtherSubModel amd om = OtherSubModel was me making an instance of it? And then when I called the *run* part of this sub-model I was passing it the parameter file. I am sensing I have this wrong? -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 14, 7:12 pm, Terry Reedy wrote: > On 2/13/2011 8:33 PM, Martin De Kauwe wrote: > > > Cool! Thanks this seems straight forward, however if I do it this way > > then once I change it (i.e. after reading user param file) I can't > > pass the changed version to another module can i? Or am I being > > stupid? Unless I do it my way I think > > > import cons > >>>> print cons.kg_as_g > >>>> 1000.0 > >>>> cons.kg_as_g = 23.4 > >>>> print cons.kg_as_g > > > is fine. > > > But if I call import cons in another module it would be back to 1000. > > right? > > Wrong. There is one and only one module object, imported into (which > means bound to a name in) as many modules as you want. If you change an > attribute, it is changed for all. If you add attributes from any module, > they are added for all, regardless of whether or not they have already > imported it. No different from changing a list or dict with multiple names. > > The math module is read only. User python-coded modules are read-write. > > -- > Terry Jan Reedy OK thanks I'll go over what I have done as I must have done something stupid as I thought I tested it earlier and couldn't get it to work like you suggested. Broadly this is how I am using it (incase it is obvious, although perhaps it just works and I need to recheck). Apart from that thanks for the modules idea it is very simple and seems to be working nicely in principle. from other_model import OtherSubModel class Model: def __init__(self): # included other external modules (i.e. in other files) om = OtherSubModel() def run(self): # call other submodel and pass params om.run(params) and the other file would look something like this class OtherSubModel: def __init__(self): #some stuff def run(params): -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 14, 12:02 pm, Terry Reedy wrote: > On 2/13/2011 6:16 PM, Martin De Kauwe wrote: > > > > > > > I think I got it, did you mean something like this? > > > class Constants: > > > radius_of_earth = 6.37122E+6 > > days_as_yrs = 1.0 / 365.25 > > m2_as_ha = 1E-4 # metres squared as hectares > > g_as_tonnes = 1E-6 # grammes as tonnes > > kg_as_tonnes = 1E-3 # kg as tonnes > > kg_as_g = 1E+3 > > > def __init__(self): > > > self.radius_of_earth = self.__class__.radius_of_earth > > self.days_as_yrs = self.__class__.days_as_yrs > > self.m2_as_ha = self.__class__.m2_as_ha > > self.g_as_tonnes = self.__class__.g_as_tonnes > > self.kg_as_tonnes = self.__class__.kg_as_tonnes > > self.kg_as_g = self.__class__.kg_as_g > > > usage something like > > >>> >from constants import Constants > >>>> Constants.kg_as_g > >>>> 1000.0 > > No, simpler. No class statememt necessarily needed. > > module constants > > > radius_of_earth = 6.37122E+6 > days_as_yrs = 1.0 / 365.25 > m2_as_ha = 1E-4 # metres squared as hectares > g_as_tonnes = 1E-6 # grammes as tonnes > kg_as_tonnes = 1E-3 # kg as tonnes > kg_as_g = 1E+3 > # could also have code to load stuff from other files > > usage > = > >>> import constants > >>> constants.kg_as_g > 1000.0 > > Real example > >>> import math > >>> math.pi, math.e > (3.141592653589793, 2.718281828459045) > > -- > Terry Jan Reedy Cool! Thanks this seems straight forward, however if I do it this way then once I change it (i.e. after reading user param file) I can't pass the changed version to another module can i? Or am I being stupid? Unless I do it my way I think import cons >>>print cons.kg_as_g >>>1000.0 >>>cons.kg_as_g = 23.4 >>>print cons.kg_as_g is fine. But if I call import cons in another module it would be back to 1000. right? Whereas if I do it as a class I can pass the adjusted instance? E.g. from constants import Constants c = Constants() I can then change "c" and pass this around? Apologies if I have got that totally wrong! -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 14, 10:16 am, Martin De Kauwe wrote: > On Feb 13, 6:35 pm, Terry Reedy wrote: > > > > > > > On 2/12/2011 9:20 PM, Martin De Kauwe wrote: > > > > On Feb 13, 5:12 am, Terry Reedy wrote: > > >> On 2/12/2011 1:24 AM, Martin De Kauwe wrote: > > > >>> The point of this posting was just to ask those that know, whether it > > >>> was a bad idea to use the class object in the way I had or was that > > >>> OK? And if I should have just used a dictionary, why? > > > >> Did you miss my suggestion to use a module rather than a class? > > >> Modules do not have some of the disadvantages of classes listed by J. > > >> Nagle. > > > >> -- > > >> Terry Jan Reedy > > > > Hi, sorry I did. I just re-read it, could you provide an example? > > > I am not sure what you are asking. tkinter.contants is one example. > > > > Sorry i am having a major mind blank this morning (I think this is > > > obvious!?). And it would meet all of the criteria outlined by John > > > Nagle? > > > A module will work fine if but only if you commit yourself to having all > > keys be legal Python identifiers. But that is usually not a problem with > > configuration values. > > > -- > > Terry Jan Reedy > > I think I got it, did you mean something like this? > > class Constants: > > radius_of_earth = 6.37122E+6 > days_as_yrs = 1.0 / 365.25 > m2_as_ha = 1E-4 # metres squared as hectares > g_as_tonnes = 1E-6 # grammes as tonnes > kg_as_tonnes = 1E-3 # kg as tonnes > kg_as_g = 1E+3 > > def __init__(self): > > self.radius_of_earth = self.__class__.radius_of_earth > self.days_as_yrs = self.__class__.days_as_yrs > self.m2_as_ha = self.__class__.m2_as_ha > self.g_as_tonnes = self.__class__.g_as_tonnes > self.kg_as_tonnes = self.__class__.kg_as_tonnes > self.kg_as_g = self.__class__.kg_as_g > > usage something like > > >>>from constants import Constants > >>>Constants.kg_as_g > >>>1000.0 > > Something similar for the params? > > thanks And then I guess define some default parameters and then use configobj to parse a .INI file. Then adjust those parameters change in the .INI file? e.g. from parameters import DefaultParameters as params # d -> comes from .INI file p = params() for key, value in d.iteritems(): # change anything read from file p.__dict__[key] = value ? -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 13, 6:35 pm, Terry Reedy wrote: > On 2/12/2011 9:20 PM, Martin De Kauwe wrote: > > > On Feb 13, 5:12 am, Terry Reedy wrote: > >> On 2/12/2011 1:24 AM, Martin De Kauwe wrote: > > >>> The point of this posting was just to ask those that know, whether it > >>> was a bad idea to use the class object in the way I had or was that > >>> OK? And if I should have just used a dictionary, why? > > >> Did you miss my suggestion to use a module rather than a class? > >> Modules do not have some of the disadvantages of classes listed by J. > >> Nagle. > > >> -- > >> Terry Jan Reedy > > > Hi, sorry I did. I just re-read it, could you provide an example? > > I am not sure what you are asking. tkinter.contants is one example. > > > Sorry i am having a major mind blank this morning (I think this is > > obvious!?). And it would meet all of the criteria outlined by John > > Nagle? > > A module will work fine if but only if you commit yourself to having all > keys be legal Python identifiers. But that is usually not a problem with > configuration values. > > -- > Terry Jan Reedy I think I got it, did you mean something like this? class Constants: radius_of_earth = 6.37122E+6 days_as_yrs = 1.0 / 365.25 m2_as_ha = 1E-4 # metres squared as hectares g_as_tonnes = 1E-6 # grammes as tonnes kg_as_tonnes = 1E-3 # kg as tonnes kg_as_g = 1E+3 def __init__(self): self.radius_of_earth = self.__class__.radius_of_earth self.days_as_yrs = self.__class__.days_as_yrs self.m2_as_ha = self.__class__.m2_as_ha self.g_as_tonnes = self.__class__.g_as_tonnes self.kg_as_tonnes = self.__class__.kg_as_tonnes self.kg_as_g = self.__class__.kg_as_g usage something like >>>from constants import Constants >>>Constants.kg_as_g >>>1000.0 Something similar for the params? thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 13, 5:12 am, Terry Reedy wrote: > On 2/12/2011 1:24 AM, Martin De Kauwe wrote: > > > The point of this posting was just to ask those that know, whether it > > was a bad idea to use the class object in the way I had or was that > > OK? And if I should have just used a dictionary, why? > > Did you miss my suggestion to use a module rather than a class? > Modules do not have some of the disadvantages of classes listed by J. Nagle. > > -- > Terry Jan Reedy Hi, sorry I did. I just re-read it, could you provide an example? Sorry i am having a major mind blank this morning (I think this is obvious!?). And it would meet all of the criteria outlined by John Nagle? -- http://mail.python.org/mailman/listinfo/python-list
Unpacking multiple dictionaries in a function?
Hi,
Is there a better way to unpack more than one dictionary in a function
than...
def unpack_dicts(f):
def wrapper(*old_dicts):
dict={}
for d in old_dicts:
dict.update(d)
return f(**dict)
return wrapper
@unpack_dicts
def some_func(a=None, b=None, c=None):
print a, b, c
d1 = {'a': 20.0, 'b': '-1'}
d2 = {'c': 33.0}
some_func(d1, d2)
thanks
--
http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 12, 8:06 pm, Martin De Kauwe wrote: > On Feb 12, 7:21 pm, Andrea Crotti wrote: > > > Il giorno 12/feb/2011, alle ore 00.45, Martin De Kauwe ha scritto: > > > > Hi, > > > > yes I read a .INI file using ConfigParser, just similar sections (in > > > my opinion) to make one object which i can then pass to different > > > classes. E.G. > > > Ok then I suggest configobj, less buggy and much more powerful than > > ConfigParser:http://www.voidspace.org.uk/python/configobj.html > > > (and included from python 2.7). > > In this way you can also simply just carry around that dictionary, and it > > will be correctly > > typed if you validate the input. > > That is interesting however I am using python 2.6 so I guess I shall > have to stick as I am for the moment. I think the way I used it above > was quite straight forward? It seemed OK? What are the issues? Ignore that I have just tested it (it works in 2.6), much better! Thanks!! -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 12, 7:21 pm, Andrea Crotti wrote: > Il giorno 12/feb/2011, alle ore 00.45, Martin De Kauwe ha scritto: > > > Hi, > > > yes I read a .INI file using ConfigParser, just similar sections (in > > my opinion) to make one object which i can then pass to different > > classes. E.G. > > Ok then I suggest configobj, less buggy and much more powerful than > ConfigParser:http://www.voidspace.org.uk/python/configobj.html > > (and included from python 2.7). > In this way you can also simply just carry around that dictionary, and it > will be correctly > typed if you validate the input. That is interesting however I am using python 2.6 so I guess I shall have to stick as I am for the moment. I think the way I used it above was quite straight forward? It seemed OK? What are the issues? -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 12, 7:22 pm, John Nagle wrote: > On 2/11/2011 6:56 AM, Martin De Kauwe wrote: > > > Hi, > > > I have a series of parameter values which i need to pass throughout my > > code (>100), in C I would use a structure for example. However in > > python it is not clear to me if it would be better to use a dictionary > > or build a class object? Personally I think accessing the values is > > neater (visually) with an object rather than a dictionary, e.g. > > > x = params['price_of_cats'] * params['price_of_elephants'] > > > vs. > > > x = params.price_of_cats * params.price_of_elephants > > Don't use a class as a dictionary. It causes various forms > of grief. A dictionary will accept any string as a key, and > has no reserved values. That's not true of class attributes. > There are already many names in a class's namespace, including > any functions of the class. Attribute syntax is restricted - > there are some characters you can't use. Unicode attributes > don't work right prior to Python 3. If the names are coming > in from outside the program, there's a potential security > hole if someone can inject names beginning with "__" and > mess with the internal data structures of the class. > And, of course, you can't use a name that's a reserved > word in Python. > > (This last is forever causing grief in programs that > parse HTML and try to use Python class attributes to > represent HTML attributes. "class" is a common HTML > attribute but a reserved word in Python. So such parsers > have to have a special case for reserved words. Ugly.) > > In Javascript, classes are simply dictionaries, but Python > is not Javascript. If you want a dictionary, use a "dict". > > John Nagle OK this was what I was after, thanks. I shall rewrite as dictionaries then given what you have said. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
Steven, You make some good points and I don't disagree with you. The code is just a transfer from some older c++ code which had all sorts of windows menus etc, which isn't required and would make it impossible to run (again and again). It is not an especially complicated model, and no doubt there are bugs (though has been used widely for 20 years). Regarding customisation, in this case it is not a big deal. The way the code was (arguably poorly) written everything was declared globally. So in fact by using the .INI file to hold all of them I am probably saving myself a lot of time and I get away from globals. Most of those parameters are things I won't change, so I take your point but I see no issue in having the option frankly (and it is done so there is no effort now!). Ordinarily I might do what you said and having method/func calls with all the params like that, but I felt it was making the code look very untidy (i.e >5 vars with each call and needing to return > 5 vars). I then decided it would be better to pass a (single) dictionary or class object (not sure of correct word here) and I think by referencing it, e.g. params.light_ext_coeff it is as clear as passing all the values individually (i.e. you can track where the values came from). I am happy with this at any rate. Moreover it is what I am used to doing in C, where I would pass a single structure containing the necessary values. I also think this is quite standard? I am sure to interface with scientific libraries (such as GNU GSL) you pass structures in this way, I was just adopting this method. The point of this posting was just to ask those that know, whether it was a bad idea to use the class object in the way I had or was that OK? And if I should have just used a dictionary, why? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
On Feb 12, 11:13 am, Steven D'Aprano wrote: > On Fri, 11 Feb 2011 10:15:27 -0800, Dan Stromberg wrote: > > I'd use a class rather than a dictionary - because with a class, pylint > > (and perhaps PyChecker and pyflakes?) should be able to detect typos > > upfront. > > *Some* typos. Certainly not all. > > The more complex the code -- and with 100 or so parameters, this sounds > pretty damn complex -- there is a non-negligible risk of mistakenly using > the wrong name. Unless pylint now has a "do what I mean, not what I say" > mode, it can't save you from typos like this: > > params.employerID = 23 > params.employeeID = 42 > # much later > if params.employeeID == 23: > # Oops, I meant employ*er*ID > ... > > > With a dictionary, typos remain runtime timebombs. > > Are your unit tests broken? You should fix that and not rely on just > pylint to detect bugs. Unit tests will help protect you against many more > bugs than just typos. > > Besides, and I quote... > > "I find it amusing when novice programmers believe their main job is > preventing programs from crashing. ... More experienced programmers > realize that correct code is great, code that crashes could use > improvement, but incorrect code that doesn't crash is a horrible > nightmare." -- Chris Smith > > -- > Steven The 100+ parameters just means "everything" can be adjusted outside of the code, invariable most of it isn't. I am setting this up with some bayesian calibration in mind. A lot of those parameters will be switches as well. I think perhaps I will write a defaults module and just read a .INI file with the values the user wants changing. Originally I was just going to read everything in, but maybe this is better from a usage point of view. As I said I am happy to consider a dictionary, although some of the calculations are quite complex and I *think* it is easier to read this way, rather than with a dictionary. That is purely an opinion, I don't have a computer science background and so I am asking really, is what I am doing very bad, and if so why? What do other people do? I have tried to search a lot on this subject but I find the example not very specific, (or I am reading the wrong places). thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
Sorry I should have added a little more example to help with clarity? So after reading the .INI file I then initialise the objects I described e.g. def initialise_simulation(self): """Set the initial conditions. using values from the .ini value set the C and N pools and other misc states. """ for attr, value in self.initial_state.__dict__.iteritems(): #print attr, value setattr(self.pools, attr, value) # maybe need M2_AS_HA here? self.pools.lai = self.params.sla * self.params.cfrac_dry_mass self.fluxes.nuptake = 0.0 -- http://mail.python.org/mailman/listinfo/python-list
Re: Class or Dictionary?
Hi,
yes I read a .INI file using ConfigParser, just similar sections (in
my opinion) to make one object which i can then pass to different
classes. E.G.
class Dict2Obj:
""" Turn a dictionary into an object.
The only purpose of this is that I think it is neater to reference
values
x.soiltemp rather than x['soiltemp'] ;P
"""
def __init__(self, dict):
for k, v in dict.items():
setattr(self, k, v)
class Parser(object):
""" Load up all the initialisation data.
Return the met data as an array, perhaps we should really also
return a
header as well? Return the ini file as various objects.
"""
def __init__(self, ini_fname, met_fname):
self.ini_fname = ini_fname
self.met_fname = met_fname
def load_files(self):
# read the driving data in, this may get more complicated?
met_data = met_data = np.loadtxt(self.met_fname, comments='#')
# read the configuration file into a different dicts, break up
# into model_params, control and state
config = ConfigParser.RawConfigParser()
config.read(self.ini_fname)
# params
model_params = {}
sections =
['water','nitra','soilp','carba','litter','envir','prodn']
for section in sections:
for option in config.options(section):
model_params[option] = config.getfloat(section,
option)
# turn dict into an object
model_params = Dict2Obj(model_params)
# control
control = {}
for option in config.options('control'):
control[option] = config.getint('control', option)
# turn dict into an object
control = Dict2Obj(control)
initial_state = {}
sections = ['cinit','ninit','vinit']
for section in sections:
for option in config.options(section):
initial_state[option] = config.getfloat(section,
option)
# turn dict into objects
initial_state = Dict2Obj(initial_state)
return (initial_state, control, model_params,
met_data)
So I would then pass these objects through my code, for example a
given class would just expect to inherit params perhaps.
class calc_weight(object):
def __init__(self, params):
self.params = params
There are also "states" that evolve through the code which various
methods of a given class change. For example lets call it elephants
weight. So the model will do various things to predict changes in our
elephants weight, so there will be a class to calculate his/her food
intake etc. Using this example the other thing I wanted to do was pass
"states" around like self.elephant_weight. However it occurred to me
if I just used self.elephant_weight for example it would make it
harder to call individual components seperately, so better to stick to
the same method and using an object i reasoned. Hence I started with
my emptydict thing, I hope that helps make it clearer?
class EmptyObject:
pass
# generate some objects to store pools and fluxes...
self.pools = EmptyObject()
# add stuff to it
self.pools.elephant_weight = 12.0
thanks for all of the suggestions it is very insightful
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Re: Class or Dictionary?
On Feb 12, 2:40 am, Andrea Crotti wrote: > On Feb 11, 3:56 pm, Martin De Kauwe wrote: > > > Hi, > > > I have a series of parameter values which i need to pass throughout my > > code (>100), in C I would use a structure for example. However in > > python it is not clear to me if it would be better to use a dictionary > > or build a class object? Personally I think accessing the values is > > neater (visually) with an object rather than a dictionary, e.g. > > > x = params['price_of_cats'] * params['price_of_elephants'] > > > vs. > > > x = params.price_of_cats * params.price_of_elephants > > Visually neater is not really a good parameter to judge. Yes and No. Makes the code easier to read and less picky to type out, in my opinion! But regarding the "no" that is why I posted the question > And in a class you can also overload __getattr__ to get the same > syntax as a dictionary. > But (>100) parameters seems really a lot, are you sure you can't split > in many classes instead? i have a number some are smaller, for example switch/control flags. But the rest can be quite large. I can split them but I don't see the advantage particularly. Currently by using them (e.g. params.rate_of_decomp) it clearly distinguishes in the code this was a model parameter read in from a file. I could create more categories but it just means more names to remember and change in the code. > > Classes have also the advantage that you can do many things behind the > scenes, while with plain dictionaries you can't do much... > Where do you take those parameters from and what are they used for? I have a big model which calculates a process, but this is made up of a number of smaller models. I have coded each of these are separate classes which expect to receive an object e.g. params, or two objects e.g. params and switches. thanks -- http://mail.python.org/mailman/listinfo/python-list
Class or Dictionary?
Hi, I have a series of parameter values which i need to pass throughout my code (>100), in C I would use a structure for example. However in python it is not clear to me if it would be better to use a dictionary or build a class object? Personally I think accessing the values is neater (visually) with an object rather than a dictionary, e.g. x = params['price_of_cats'] * params['price_of_elephants'] vs. x = params.price_of_cats * params.price_of_elephants So currently I am building a series of class objects to hold different parameters and then passing these through my code, e.g. class EmptyObject: pass self.animal_prices = EmptyObject() self.price_of_cats = 12 or reading a file and populating the object I would be keen to hear any reasons why this is a bad approach (if it is, I haven't managed to work this out)? Or perhaps there is a better one? thanks Martin -- http://mail.python.org/mailman/listinfo/python-list
Re: code structure advise for a model
On Feb 4, 8:41 pm, Marco Nawijn wrote:
> On Feb 4, 3:43 am, Martin De Kauwe wrote:
>
>
>
>
>
> > Hi,
>
> > I am translating some c++ code to python and just wanted to ask some
> > advise on structure. The original has everything declared globally and
> > nothing passed via function (I assume, but don't know, that this isn't
> > just standard c++ practice!). So given this, I have a pretty much
> > clean slate as I can't quite just copy the functions over. I was
> > thinking something like this
>
> > class Params:
>
> > def __init__(self, fname):
> > self.set_inital_condtions()
> > self.read_input_file(fname)
>
> > def set_inital_conditons(self):
> > self.some_parm = 0.0
>
> > def read_input_file(fname):
>
> > #read file, change initial params if specified
>
> > then I thought I could pass this as an object to the model class
>
> > class Model(Params):
>
> > def __init__(self):
> > # blah
>
> > def some_func(self):
> > if (Params.some_param == something):
> > foo
>
> > OR this just a very bad way to structure it?
>
> > The other thing I can't decide on is how to pass the parameters and
> > variables through the class. So because of the way the original is
> > written (everything is global), I could just inherit things, but it
> > does means there is a lot of self. syntax. So I wondered if it might
> > be better to pass things as function arguments? Any thoughts? I am
> > also half considering other users from non-python backgrounds and what
> > might seem very alien (syntax) to them.
>
> > thanks in advance
>
> > (ps. I am cross posting this on comp.lang.python as I am not sure
> > where is more appropriate).
>
> I would structure it in three classes/functions:
> 1. A parser class/function that reads an input file and returns a
> Parameters object
> 2. A Parameters class
> 3. A Model class that uses the Parameters
>
> You would end up with something like the following:
>
> class MyParser(object):
>
> def __init__(self, filename=None):
> self.filename = filename
>
> def parse(self, filename):
>
> params = Parameters()
>
> ...read info from filename and update parameters
>
> return params
>
> class Parameters(object):
>
> def __init__(self):
> self.myAttribute1 = 0
> self.myAttribute2 = "A string"
>
> class MyModel(object):
>
> def __init__(self, parameters):
> self.parameters = parameters
>
> def solve(self):
> ...solve the problem
>
> The driver program would look something like this:
>
> parser = MyParser()
>
> params = parser.parse('inputfile')
>
> model = MyModel(params)
> model.solve()
>
> I hope this is helpfull for you.
>
> Regards,
>
> Marco
thanks for that. I decided to read the params straight into a set of
dictionaries and then pass these dictionaries around the various model
methods.
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code structure advise for a model
Hi, I am translating some c++ code to python and just wanted to ask some advise on structure. The original has everything declared globally and nothing passed via function (I assume, but don't know, that this isn't just standard c++ practice!). So given this, I have a pretty much clean slate as I can't quite just copy the functions over. I was thinking something like this class Params: def __init__(self, fname): self.set_inital_condtions() self.read_input_file(fname) def set_inital_conditons(self): self.some_parm = 0.0 def read_input_file(fname): #read file, change initial params if specified then I thought I could pass this as an object to the model class class Model(Params): def __init__(self): # blah def some_func(self): if (Params.some_param == something): foo OR this just a very bad way to structure it? The other thing I can't decide on is how to pass the parameters and variables through the class. So because of the way the original is written (everything is global), I could just inherit things, but it does means there is a lot of self. syntax. So I wondered if it might be better to pass things as function arguments? Any thoughts? I am also half considering other users from non-python backgrounds and what might seem very alien (syntax) to them. thanks in advance (ps. I am cross posting this on comp.lang.python as I am not sure where is more appropriate). -- http://mail.python.org/mailman/listinfo/python-list
