Turn list into list of lists depending on values and then plot using matplotlib

Question

i got two lists and I am trying to plot the 5 values as a red line and the 0 as a blue line at a fixed y-value. My lists are similar to these two:

main_list = [5, 5, 5, 5, 5, 5, 0, 0, 0, 0, 5, 5, 5, 5, 5, 5, 0, 0, 5, 0, 0]
x_axis = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]

I tried to get this output so i could plot each sub-list as a new plot with either the color red for 5 and color blue for 0:

main_list = [[5, 5, 5, 5, 5, 5], [0, 0, 0, 0], [5, 5, 5, 5, 5, 5], [0, 0],[5],[0, 0]]

I have tried the following but I cant seem to get the correct output. I have the feeling that my approach is wrong but I cant think of a different solution.

def split_list(list):
  main_list = [[i] for i in list]
  for i,sub_list in enumerate(main_list):
    if(i<len(main_list)-1):
     if(sub_list[0]==main_list[i+1][0]):
      main_list[i+1] = sub_list+ main_list[i+1] 
      del main_list[i]
  return main_list

but my output is :

main_list = [[5, 5], [5, 5], [5, 5], [0, 0], [0, 0], [5, 5], [5, 5], [5, 5], [0, 0], [5], [0, 0]]

mozway · Accepted Answer · 2021-11-26 14:22:26Z

splitting the data

easy version: y-data only

An easy way to split the list like you want is to use itertools.groupby:

from itertools import groupby
ys = [list(g) for k,g in groupby(main_list)]

output:

>>> ys
[[5, 5, 5, 5, 5, 5], [0, 0, 0, 0], [5, 5, 5, 5, 5, 5], [0, 0], [5], [0, 0]]

combined x and y

Now it gets slightly more complex if you want to align the two lists. You can use zip:

[list(zip(*g)) for k,g in groupby(zip(x_axis, main_list), lambda x: x[1])]

output:

[[(0, 1, 2, 3, 4, 5), (5, 5, 5, 5, 5, 5)],
 [(6, 7, 8, 9), (0, 0, 0, 0)],
 [(10, 11, 12, 13, 14, 15), (5, 5, 5, 5, 5, 5)],
 [(16, 17), (0, 0)],
 [(18,), (5,)],
 [(19, 20), (0, 0)]]

If you prefer to have two output lists, you can do:

xs, ys = list(zip(*(list(zip(*g)) for k,g in groupby(zip(x_axis, main_list), lambda x: x[1]))))

output:

>>> xs
((0, 1, 2, 3, 4, 5),
 (6, 7, 8, 9),
 (10, 11, 12, 13, 14, 15),
 (16, 17),
 (18,),
 (19, 20))

>>> ys
 ((5, 5, 5, 5, 5, 5), (0, 0, 0, 0), (5, 5, 5, 5, 5, 5), (0, 0), (5,), (0, 0)))

plotting

import matplotlib.pyplot as plt

groups = (list(zip(*g)) for k,g in groupby(zip(x_axis, main_list), lambda x: x[1]))

colors = {0: 'blue', 5: 'red'}
ax = plt.subplot()
for x,y in groups:
    ax.plot(x, y, marker='o', c=colors[y[0]])

output:

Collectives™ on Stack Overflow

Turn list into list of lists depending on values and then plot using matplotlib

1 Answer 1

splitting the data

easy version: y-data only

combined x and y

plotting

Comments

Your Answer

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Collectives™ on Stack Overflow

1 Answer 1

splitting the data

easy version: y-data only

combined x and y

plotting

Comments

Your Answer

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