无法 plot 直方图（hist2d）

Question

Trying to plot length of objects vs total count of objects using hist2d. I am getting the following error. Can you please help me in finding the error.

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

count=799.000000

plt.hist2d(length,count,bins = 10)

plt.xlabel('count')
plt.ylabel('length')
plt.grid(True)
plt.show()
print(length)
1      3.978235
2      4.740024
3      3.470375
4      3.978235
5      3.808948
         ...   
807    5.078597
808    4.655381
809    4.232164
810    4.655381
811    3.470375
Name: length_mm, Length: 799, dtype: float64

Answer 1

I believe the issue in you code is the use of hist2d rather than the good-old hist . With hist , you don't have to pass the number of items - it gets that from the Series:

plt.hist(length, bins = 10)
plt.xlabel('count')
plt.ylabel('length')
plt.grid(True)
plt.show()

The result (for a small amount of data) is:

If, on the other hand, you'd looking for a bar chart, here's the way to do it for length :

fig, ax = plt.subplots()
ax.bar(length.index, length)
fig.show()

The result (for limited data, of course) is: