Plot dates in histogram from clipboard by month (Python2)

date_histogramm.py

import sys
import numpy as np
# ~from io import StringIO
import matplotlib.pyplot as plt
import pyperclip
from datetime import datetime
import matplotlib.dates as mdates
from matplotlib.dates import date2num
from dateutil.relativedelta import relativedelta

def getdate(s):
	return s.strip().split(' ')[0].strip()

def datestr2dateobj(datestr):
	try:
		return datetime.strptime(datestr, '%d.%m.%Y') # '%d.%m.%Y %H:%M:%S'
	except ValueError:
		return None

def getmonthdelta(end_date,start_date):
	return (end_date.year - start_date.year) * 12 + (end_date.month - start_date.month)

cliptext = pyperclip.paste()
# ~cliptext = "5.1.2019\n10.1.2019\n11.01.2019\n3.2.2019\n3.3.2019\n4.3.2019\n13.3.2019"

data = cliptext.split("\n")

# ~data = np.genfromtxt(StringIO(cliptext), delimiter="\t", dtype=None, encoding=None)
# ~print data.shape
# ~data = data[:,0] # reduce to one column if there are multiple

dates = [datestr2dateobj(getdate(date)) for date in data]
dates = [x for x in dates if x]
print "data: len =", len(dates)

if (not dates):
	print "no data, exiting"
	sys.exit()

date_min = min(dates)
date_max = max(dates)
print "min = ",date_min
print "max = ",date_max

md = getmonthdelta(date_max,date_min)
print "month between: ",md


# define first bin to plot
nullmonth = date_min.replace(day=1)
# get a list of all months to bin in histogram
monthlist = []
onemonth = relativedelta(months=1)
for i in range(md+1):
    monthlist.append(nullmonth + i*onemonth) # alternative: add one month until the end date is passed
monthlist_plot = date2num(monthlist)
print "month list: len=", len(monthlist),', min= ', min(monthlist),', max= ', max(monthlist)
# ~print monthlist_plot
# ~print "dates= ",dates
mpl_data = date2num(dates)


# ~# PLOT
fig, ax = plt.subplots()

ax.hist(mpl_data, bins = monthlist_plot)
plt.title("histogram")

# format the ticks
years = mdates.YearLocator()   # every year
months = mdates.MonthLocator()  # every month
years_fmt = mdates.DateFormatter('%Y')
month_fmt = mdates.DateFormatter('%m')
ax.xaxis.set_major_locator(years)
ax.xaxis.set_major_formatter(years_fmt)
ax.xaxis.set_minor_locator(months)
ax.xaxis.set_minor_formatter(month_fmt)
# ~ax.xaxis.set_tick_params(rotation=45)
ax.tick_params(axis='x', rotation=90)
fig.autofmt_xdate(bottom=0.2, rotation=30, ha='right')
plt.show()


# ~plt.hist(mpl_data, bins = monthlist_plot, ec="k")
# ~plt.gcf().autofmt_xdate()
# ~plt.show()