From list of objects to plotting

Community matplotlib-users
1

I have some code that simplified looks like this:

class cKBO(object):
  def __init__(cls):
    cls.a = 0.
    cls.e = 0.

lines = open("test.file","r").readlines()

nlist = []
for line in lines:
  obj = cKBO()
  (a,e) = line.split
  obj.a = float(a)
  obj.e = float(e)
  nlist.append(obj)

I would now like to plot a vs e for all the obj objects in nlist.
how do I do that? I tried

plot(nlist[:].a,nlist[:].e,'ko')
show()

but that resulted in
raceback (most recent call last):
   File "/Users/tgrav/Work/MyCode/Python/MOPS/ckbos.py", line 108, in ?
     plot(nlist[:].a,nlist[:].e,'ko')
AttributeError: 'list' object has no attribute 'a'

Which is understandable. But how do I most easily convert a list of class
objects into two lists of object variables?

Cheers
   Tommy

2

Hello Tommy,

I would like to do such convertings, too, but I think there is no such fast
way in python. I'm using the 'for statement' to iterate over a list of
objects and save their properties into a new list.

best regards,
Matthias

···

On Friday 04 May 2007 17:54, Tommy Grav wrote:

I have some code that simplified looks like this:

class cKBO(object):
  def __init__(cls):
    cls.a = 0.
    cls.e = 0.

lines = open("test.file","r").readlines()

nlist =
for line in lines:
  obj = cKBO()
  (a,e) = line.split
  obj.a = float(a)
  obj.e = float(e)
  nlist.append(obj)

I would now like to plot a vs e for all the obj objects in nlist.
how do I do that? I tried

plot(nlist[:].a,nlist[:].e,'ko')
show()

but that resulted in
raceback (most recent call last):
   File "/Users/tgrav/Work/MyCode/Python/MOPS/ckbos.py", line 108, in ?
     plot(nlist[:].a,nlist[:].e,'ko')
AttributeError: 'list' object has no attribute 'a'

Which is understandable. But how do I most easily convert a list of
class
objects into two lists of object variables?

Cheers
   Tommy

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