Re: [Matplotlib-users] plot a data stream with matplotlib

[C L. <ch...@na...>]

#Skeleton example of a taking snapshots of an evolving class
import pylab as p
from math import log
class foo:
     def __init__(self):
         self.red = 0
         self.green = 1
         self.age = 0
         self.history = ([self.age],[self.red],[self.green])

     def snapshot(self):
         self.history[0].append(self.age)
         self.history[1].append(self.red)
         self.history[2].append(self.green)

     def evolve(self, time):
         self.red = self.red + time/2
         self.green = self.green * log(time)
         self.age = self.age + time
         self.snapshot()

     def display(self):
          
p.plot(self.history[0],self.history[1],self.history[0],self.history[2])
         p.show()

if __name__ == '__main__':
     f = foo()
     f.snapshot()
     f.evolve(6); f.evolve(.27);f.evolve(10);f.evolve(2)
     print f.history
     f.display()

On Jan 18, 2009, at 3:18 PM, Simone Gabbriellini wrote:

> thanks, it is exactly what I need... I have undestood the logic, I
> build a plot,  put my traits values into an array and then I call the
> add_current_state_to_plot function to update the plot with the new
> values...
>
> I am an absolute beginner of matplotlib, can you give me a little
> example of add_current_state_to_plot function? Because I don't know
> the right way to update: do I have to pass all the array, or just the
> new values?
>
> best regards,
> simone
>
> 2009/1/18 C Lewis <ch...@na...>:
>> Guessing about what you want:
>>
>> Does the class change with time? that is, perhaps you have a class  
>> foo, and
>> foo evolves, and you would like to plot a history of some traits of  
>> foo, but
>> at any given moment foo only contains its current state?
>>
>> If so, I think you need to have a function in foo, or even a  
>> separate class,
>> that takes `snapshots' of foo's traits on one schedule, and stores  
>> them, and
>> can also plot them on some schedule. Choosing how to do that is  
>> more a
>> python problem than a matplotlib problem; personally, I have  
>> something set
>> up so class 'profile' has functions to 'setup_plot' and
>> 'add_current_state_to_plot', and I just have to choose when to call  
>> the
>> latter.
>>
>> Or you can just store the values and plot at the end; once you have  
>> one list
>> of the times, and a separate list of each trait's history at those  
>> times,
>> you're set up for matplotlib plotting, e.g.
>>
>> from pylab import *
>> plot(times, traitA, times, traitB, times, traitC)
>> show()
>>
>> although, while looking for a simple example, I found this:
>>
>> http://matplotlib.sourceforge.net/examples/pylab_examples/plotfile_demo.html
>>
>> which is not totally simple but looks great.
>>
>>
>> &C
>>
>> On Jan 18, 2009, at 9:36 AM, Simone Gabbriellini wrote:
>>
>>> Dear List,
>>>
>>> I have some variables I want to plot... the values of those variable
>>> change in time... I would like to plot the result with a traditional
>>> line plot
>>>
>>> those variables are traits of a class (don't know if this can make a
>>> difference...)
>>>
>>> is there any example of this with matplotlib?
>>>
>>> best regards,
>>> simone gabbriellini
>>>
>>>
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>>

Chloe Lewis
Graduate student, Amundson Lab
Division of Ecosystem Sciences, ESPM
University of California, Berkeley
137 Mulford Hall - #3114
Berkeley, CA  94720-3114
ch...@na...