Get the height of the rectangles in a plot-CodePudding

I have the following graph

[2] The code I used is the following:

import pandas as pd
import matplotlib.ticker as ticker
import matplotlib.pyplot as plt
import numpy as np

dfLunedi = pd.read_csv( "0.lun.csv", encoding = "ISO-8859-1", sep = ';')

dfSlotMean = dfLunedi.groupby('slotID', as_index=False).agg( NLunUn=('date', 'nunique'),NLunTot = ('date', 'count'), MeanBPM=('tempo', 'mean'), std = ('tempo','std') )
#print(dfSlotMean)

dfSlotMean.drop(dfSlotMean[dfSlotMean.NLunUn < 3].index, inplace=True)
    
df = pd.DataFrame(dfSlotMean)

df.to_csv('1.silLunedi.csv', sep = ';', index=False)

print(df)

bpmMattino = df['MeanBPM']
std = df['std']
listBpm = bpmMattino.tolist()

limInf = df['MeanBPM'] - df['std']
limSup = df['MeanBPM']   df['std']

tick_spacing = 1
fig, ax = plt.subplots(1, 1)
for _, r in df.iterrows():
    #
    ax.plot([r['slotID'], r['slotID'] 1], [r['MeanBPM']]*2, linewidth = r['std'] )
    #ax.plot([r['slotID'], r['slotID'] 1], [r['MeanBPM']]*2, linewidth = r['std'])
    ax.xaxis.grid(True)
    ax.yaxis.grid(True)
    ax.yaxis.set_major_locator(ticker.MultipleLocator(tick_spacing))
    ax.xaxis.set_major_locator(ticker.MultipleLocator(tick_spacing))

CodePudding user response：

If you define the height as the standard deviation, and the center is at the mean, then the interval should be [mean-(std/2) ; mean (std/2)] for each rectangle right? Is it intentional that the rectangles overlap? If not, I think it is your use of linewidth to size the rectangles which is at fault. If the plot is there to visualize the mean and variance of the different categories something like a boxplot or raincloud plot might be better.

CodePudding user response：

I would advise against using linewidth to show anything related to your data. The reason being that linewidth is measured in "points" (see the matplotlib documentation), the size of which are not related to the xy-space that you plot your data in. To see this in action, try plotting with different linewidths and changing the size of the plotting-window. The linewidth will not change with the axes.

Instead, if you do indeed want a rectangle, I suggest using matplotlib.patches.Rectangle. There is a good example of how to do that in the documentation, and I've also added an even shorter example below.

import matplotlib.pyplot as plt
import matplotlib.patches as ptc

x = 3
y = 4.5
y_std = 0.3

fig, ax = plt.subplots()
rect = ptc.Rectangle(xy=(x, y-y_std), width=2, height=2*y_std)
ax.add_patch(rect)
ax.set_xlim((0,10))
ax.set_ylim((0,5))
plt.show()