matplotlib TypeError: unsupported operand type(s) for -: 'datetime.date' and 'float'

Question

I've got an error with the code below. This plot works well in Python2, but in Python3 i've got TypeError. Have no idea, how to fix it.

import matplotlib.pyplot as plt
from pylab import rcParams
import matplotlib.ticker as mtick
import matplotlib.dates as mdates
import numpy as np
import pandas as pd
from datetime import datetime, timedelta

DF = pd.DataFrame({
    'day':     [datetime(2018,1,1).date()+timedelta(x+1) for x in range(100)],
    'balance': np.random.normal(100,100,100)
})
rcParams['figure.figsize'] = 20, 10
fig, ax = plt.subplots()
ax.bar(DF['day'], DF['balance'], color='lightblue')
plt.xlabel('day', fontsize=20)
myFmt = mdates.DateFormatter('%Y-%m')
ax.xaxis.set_major_formatter(myFmt)
plt.show()

Error:

TypeError Traceback (most recent call last) in () 5 rcParams['figure.figsize'] = 20, 10 6 fig, ax = plt.subplots() ----> 7 ax.bar(DF['day'], DF['balance'], color='lightblue') 8 plt.xlabel('day', fontsize=20) 9 myFmt = mdates.DateFormatter('%Y-%m')

/home/anaconda3/lib/python3.6/site-packages/matplotlib/init.py in inner(ax, *args, **kwargs) 1896
warnings.warn(msg % (label_namer, func.name), 1897
RuntimeWarning, stacklevel=2) -> 1898 return func(ax, *args, **kwargs) 1899 pre_doc = inner.doc 1900 if pre_doc is None:

/home/anaconda3/lib/python3.6/site-packages/matplotlib/axes/_axes.py in bar(self, left, height, width, bottom, **kwargs) 2103 if align == 'center': 2104 if orientation == 'vertical': -> 2105 left = [left[i] - width[i] / 2. for i in xrange(len(left))] 2106 elif orientation == 'horizontal': 2107 bottom = [bottom[i] - height[i] / 2.

/home/anaconda3/lib/python3.6/site-packages/matplotlib/axes/_axes.py in (.0) 2103 if align == 'center': 2104
if orientation == 'vertical': -> 2105 left = [left[i] - width[i] / 2. for i in xrange(len(left))] 2106 elif orientation == 'horizontal': 2107 bottom = [bottom[i] - height[i] / 2.

TypeError: unsupported operand type(s) for -: 'datetime.date' and 'float'

Rakesh Rakesh · Accepted Answer · 2018-04-27T10:55:37

Use date2num on the date column

Ex:

import matplotlib.pyplot as plt
from pylab import rcParams
import matplotlib.ticker as mtick
import matplotlib.dates as mdates
from matplotlib.dates import date2num       #-->Update
import numpy as np
import pandas as pd
from datetime import datetime, timedelta

DF = pd.DataFrame({
    'day':     [datetime(2018,1,1).date()+timedelta(x+1) for x in range(100)],
    'balance': np.random.normal(100,100,100)
})
rcParams['figure.figsize'] = 20, 10
fig, ax = plt.subplots()
DF['day'] = DF['day'].apply(date2num)      #-->Update

ax.bar(DF['day'], DF['balance'], color='lightblue')
plt.xlabel('day', fontsize=20)
myFmt = mdates.DateFormatter('%Y-%m')
ax.xaxis.set_major_formatter(myFmt)
plt.show()

matplotlib TypeError: unsupported operand type(s) for -: 'datetime.date' and 'float'

1 Answers