Plotting python object attribute and objects are stored in list

Question

I have objects stored in list called lst in python. I need to plot just one objects attribute as a plot.

import numpy as np
import matplotlib.pyplot as plt

class Particle(object):
    def __init__(self, value = 0, weight = 0):
        self.value = value
        self.weight = weight
lst = []
for x in range(0,10):
    lst.append(Particle(value=np.random.random_integers(10), weight = 1))

I tried this and it works, but I think it is not very 'pythonic' way:

temp = [] #any better idea? 
for x in range(0,len(lst)):
    temp.append(l[x].value)
plt.plot(temp, 'ro')

what do you suggest, how to plit it in more pythonic way? Thank you

Answer 1

Use a list comprehension to generate a list of your values.

import numpy as np
import matplotlib.pyplot as plt

class Particle(object):
    def __init__(self, value = 0, weight = 0):
        self.value = value
        self.weight = weight
lst = []
for x in range(0,10):
    lst.append(Particle(value=np.random.random_integers(10), weight = 1))

values = [x.value for x in lst]

plt.plot(values, 'ro')
plt.show()

The list comprehension is equivalent to the following code:

values = []
for x in lst:
    values.append(x.value)

Note that you could also tidy up the creation of your lst collection with another list comprehension

lst = [(Particle(value=np.random.random_integers(10), weight=1) for _ in range(10)]