How to add scientific labels to histogram plots?

Question

I'm trying to print scientific labels above each bar plot, similar to my y-axis that already is set to a scientific notation. I've tried using "{:.2E}".format but that doesnt work as i'm trying to convert an entire array (count). Any ideas?

xx= np.arange(0,10) , labels = [0.2,0.1,0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0]

plt.figure(figsize=(7, 4.5)) , plt.bar(xx, count), plt.xlabel('base.distance') , plt.xticks(xx, labels)

addlabels(xx,count.astype('int32'))

plt.ticklabel_format(axis='y', style='sci', scilimits=(0,0))

plt.ylabel('Count'), plt.title(file), plt.show()

That doesn't change anything @Redox – Tess Oct 14 '22 at 14:05 — Tess, Oct 14 '22 at 14:05
Pls provide data for `count`. What does `addlabels()` do? – Redox Oct 14 '22 at 15:18 — Redox, Oct 14 '22 at 15:18

score 1 · Accepted Answer · answered Oct 15 '22 at 00:45

Barplots have a helper function to add labels, which will format them, but the docs for it show an old style of formatting-string (often called printf formatting). If you want all the control of format-strings, you can make a list of labels. Try this:

import numpy as np
import matplotlib.pyplot as plt
import random

xx= np.arange(0,10)
labels = [0.2,0.1,0.0,1.0,2.0,3.0,4.0,5.0,6.0,7.0]
count = random.sample(range(3000,14000), len(xx))

fig, ax = plt.subplots(figsize=(7, 4.5))
barplot = ax.bar(xx, count)
plt.xlabel('base.distance')
plt.xticks(xx, labels)

#ax.bar_label(barplot) # the whole numbers
#ax.bar_label(barplot, fmt='%2.1e') #old school
ax.bar_label(barplot, labels=map(lambda x: '{:.2E}'.format(x), count))


plt.ticklabel_format(axis='y', style='sci', scilimits=(0,0))

plt.ylabel('Count')
plt.show()

How to add scientific labels to histogram plots?

1 Answers1