Hello All.
I just found a bug with the histogramme fonction of matplotlib.
It might been already known, in this case don’t pay attention to my message.
The bug append with both OS: Windows XP and Linux (ubuntu). Both using the latest matplotlib release: 0.99.1
The bug is reproductible, with the folliwng script:
What the script shall do:
Let’s say you are looking at the color of wagons on trains.
Every trains has 31 wagons.
Each time you see a red one, you write down it’s number
At the end, you want to draw the histogramme with
X axis: Number of the wagon in the tain
Y axis: Number of wagon of a specific number which is red.
My script
···
#------------------------------------------------------------------------------------------------------------------------------
import matplotlib.pyplot as
plt
liste_histo=[2,2,2,6,1,2,7,2,1,2,1,2,2,1,2,2,11,1,2,12,2,2,14,2,2,1,2,6,1,2,2]
plt.figure(1)
plt.hist(sorted(liste_histo),bins=31)
plt.axis([0,31,0,20])
plt.show()
#-----------------------------------------------------------------------------------------------------------------------------
This script should give you a srange historamme, with bins that are half the size they shoud be.
With the same script, but a different countdown of my wagons, it works well:
#-----------------------------------------------------------------------------------------------------------------------------
import matplotlib.pyplot as
plt
liste_histo=[2,2,2,6,1,2,7,2,1,2,1,2,2,1,2,2,11,1,2,12,2,2,14,2,2,1,2,6,15,25]
plt.figure(1)
plt.hist(sorted(liste_histo),bins=31)
plt.axis([0,31,0,20])
plt.show()
#-----------------------------------------------------------------------------------------------------------------------------
I corrected this error by adding a 32 (my max value on the histogramme should be a 31).
asking 32 bins, and drawing the histogramme between 1 and 31:
#------------------------------------------------------------------------------------------------------------------------------
import matplotlib.pyplot as plt
liste_histo=[2,2,2,6,1,2,7,2,1,2,1,2,2,1,2,2,11,1,2,12,2,2,14,2,2,1,2,6,1,2,2,32]
plt.figure(1)
plt.hist(sorted(liste_histo),bins=32)
plt.axis([0,31,0,20])
plt.show()
#-----------------------------------------------------------------------------------------------------------------------------
And it works…
Am I the only one to get a probleme here?
Thanks for reading me
Julien