Bar plot with different minimal value for each bar - python-3.x

Question

I'm trying to reproduce this type of graph :
basically, the Y axis represent the date of beginning and end of a phenomenon for each year.
but here is what I have when I try to plot my data :
It seems that no matter what, the bar for each year is plotted from the y axis minimal value.
Here is the data I use
Here is my code :
select=pd.read_excel("./writer.xlsx")
select=pd.DataFrame(select)
select["dte"]=pd.to_datetime(select.dte)
select["month_day"]=pd.DatetimeIndex(select.dte).strftime('%B %d')
select["month"]=pd.DatetimeIndex(select.dte).month
select["day"]=pd.DatetimeIndex(select.dte).day
gs=gridspec.GridSpec(2,2)
fig=plt.figure()
ax1=plt.subplot(gs[0,0])
ax2=plt.subplot(gs[0,1])
ax3=plt.subplot(gs[1,:])
###2 others graphs that works just fine
data=pd.DataFrame()
del select["res"],select["Seuil"],select["Seuil%"] #these don't matter for that graph
for year_ in list(set(select.dteYear)):
temp=select.loc[select["dteYear"]==year_]
temp2=temp.iloc[[0,-1]] #the beginning and ending of the phenomenon
data=pd.concat([data,temp2]).reset_index(drop=True)
data=data.sort_values(["month","day"])
ax3.bar(data["dteYear"],data["month_day"],tick_label=data["dteYear"])
plt.show()
If you have some clue to help me, I'd really appreciate, because I havn't found any model to make this type of graph.
thanks !
EDIT :
I tried something else :
height,bottom,x_position=[], [], []
for year_ in list(set(select.dteYear)):
temp=select.loc[select["dteYear"]==year_]
bottom.append(temp["month_day"].iloc[0])
height.append(temp["month_day"].iloc[-1])
x_position.append(year_)
temp2=temp.iloc[[0,-1]]
data=pd.concat([data,temp2]).reset_index(drop=True)
ax3.bar(x=x_position,height=height,bottom=bottom,tick_label=x_position)
I got this error :
Traceback (most recent call last):
File "C:\Users\E31\Documents\cours\stage_dossier\projet_python\tool_etiage\test.py", line 103, in <module>
ax3.bar(x=x_position,height=height,bottom=bottom,tick_label=x_position)
File "C:\Users\E31\AppData\Local\Programs\Python\Python39\lib\site-packages\matplotlib\__init__.py", line 1352, in inner
return func(ax, *map(sanitize_sequence, args), **kwargs)
File "C:\Users\E31\AppData\Local\Programs\Python\Python39\lib\site-packages\matplotlib\axes\_axes.py", line 2357, in bar
r = mpatches.Rectangle(
File "C:\Users\E31\AppData\Local\Programs\Python\Python39\lib\site-packages\matplotlib\patches.py", line 752, in __init__
super().__init__(**kwargs)
File "C:\Users\E31\AppData\Local\Programs\Python\Python39\lib\site-packages\matplotlib\patches.py", line 101, in __init__
self.set_linewidth(linewidth)
File "C:\Users\E31\AppData\Local\Programs\Python\Python39\lib\site-packages\matplotlib\patches.py", line 406, in set_linewidth
self._linewidth = float(w)
TypeError: only size-1 arrays can be converted to Python scalars

Answer 1

To make a bar graph that shows a difference between dates you should start by getting your data into a nice format in the dataframe where it is easy to access the bottom and top values of the bar for each year you are plotting. After this you can simply plot the bars and indicate the 'bottom' parameter. The hardest part in your case may be specifying the datetime differences correctly. I added a x tick locator and y tick formatter for the datetimes.
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import matplotlib as mpl
import matplotlib.dates as mdates
# make function that returns a random datetime
# between a start and stop date
def random_date(start, stop):
days = (stop - start).days
rand = np.random.randint(days)
return start + pd.Timedelta(rand, unit='days')
# simulate poster's data
T1 = pd.to_datetime('July 1 2021')
T2 = pd.to_datetime('August 1 2021')
T3 = pd.to_datetime('November 1 2021')
df = pd.DataFrame({
'year' : np.random.choice(np.arange(1969, 2020), size=15, replace=False),
'bottom' : [random_date(T1, T2) for x in range(15)],
'top' : [random_date(T2, T3) for x in range(15)],
}).sort_values(by='year').set_index('year')
# define fig/ax and figsize
fig, ax = plt.subplots(figsize=(16,8))
# plot data
ax.bar(
x = df.index,
height = (df.top - df.bottom),
bottom = df.bottom,
color = '#9e7711'
)
# add x_locator (every 2 years), y tick datetime formatter, grid
# hide top/right spines, and rotate the x ticks for readability
x_locator = ax.xaxis.set_major_locator(mpl.ticker.MultipleLocator(2))
y_formatter = ax.yaxis.set_major_formatter(mdates.DateFormatter('%d %b'))
tick_params = ax.tick_params(axis='x', rotation=45)
grid = ax.grid(axis='y', dashes=(8,3), alpha=0.3, color='gray')
hide_spines = [ax.spines[s].set_visible(False) for s in ['top','right']]