Question

I have data in a hashmap, and I want to create a histogram over this data using the keys as bins and the values as data.

My data:

N = {1: 12, 2: 15, 3: 8, 4: 4, 5: 1}

What I want plotted:

  |
15|    X
  |    X 
  |    X
  | X  X
  | X  X
10| X  X
  | X  X
  | X  X  X
  | X  X  X
  | X  X  X
 5| X  X  X
  | X  X  X  X
  | X  X  X  X
  | X  X  X  X
  | X  X  X  X  X
  |_________________________
    1  2  3  4  5

I’ve tried to figure out how to do this with pyplot.hist(), but all overloads I can find take a list of values, not a hashmap. Do I really have to generate this list, just to let matplotlib count all the values again?

Answer 1

Just plot a bar graph. That’s all hist does.

E.g.:

import matplotlib.pyplot as plt

N = {1: 12, 2: 15, 3: 8, 4: 4, 5: 1}
plt.bar(N.keys(), N.values(), align='center')
plt.show()