Stackplot using list of dictionary values (Python 3.x)

Question

I am trying to make a stackplot from a dictionary where the value is a list of floats between 0 and 1 and the index of the value in the list is the time (t1, t2, ...tn) of measurement. All keys have the same number of values. For example:

a = {1:[0.3,0.5,0.7], 2:[0.4,0.6,0.8], 5:[0.1,0.15,0.20]}

so that at t2: a[1] = 0.5, a[2] = 0.6, and a[5] = 0.15, and so on at the other indices of the list of values.

I'm going for a stackplot like the one here with the indices of the value list on the x-axis and the value of a[i] at that index on the y-axis , but can't figure out how to adapt that code or the matplotlib example to a dictionary.

Python version: 3.4

Error (for both my data and toy data set): TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

Suggestions?

Answer 1

UPDATE - The error you are getting is because matplotlib is somehow not happy with the view you are getting from dict.values(). Note that this is only a problem of python 3.x as for python 2.x dict.values() returns a list. You can simply avoid this problem by converting the view into a normal list, so list(dict.values()).

Here is the matplotlib example using a dict, working for both python 2.x and 3.x:

import numpy as np
from matplotlib import pyplot as plt

fnx = lambda : np.random.randint(5, 50, 10).astype(np.float64)
d = {i: v for i, v in enumerate(np.row_stack((fnx(), fnx(), fnx())))}
# d looks basically like your a
x = range(len(d[0]))
y = list(d.values()) # d.values() returns a view in python 3.x
fig, ax = plt.subplots()
ax.stackplot(x, y)
plt.show()