matplotlib.pyplot.plot_date() in Python

Last Updated : 12 Jul, 2025

Matplotlib is a library in Python and it is numerical - mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.plot_date() Function:

The plot_date() function in pyplot module of matplotlib library is used to plot with data that contains dates.

Syntax:
matplotlib.pyplot.plot_date(x, y, fmt='o', tz=None, xdate=True, ydate=False, hold=None, data=None, **kwargs)
Parameters: This method accept the following parameters that are described below:

x, y: These parameter are the horizontal and vertical coordinates of the data points.

fmt: This parameter is an optional parameter and it contains the string value.

tz: This parameter is the time zone to use in labeling dates.It contain timezone string.

xdate: This parameter is also an optional parameter. And it contain boolean values with default value True. If True, the x-axis will be interpreted as Matplotlib dates.

ydate: This parameter is also an optional parameter. And it contain boolean values with default value True. If True, the y-axis will be interpreted as Matplotlib dates.

Returns: This returns the following:

lines:This returns the list of Line2D objects representing the plotted data.

Below examples illustrate the matplotlib.pyplot.plot_date() function in matplotlib.pyplot: Example #1:

Python3

# Implementation of matplotlib function
import datetime
import matplotlib.pyplot as plt
from matplotlib.dates import drange
import numpy as np
 
date1 = datetime.datetime(2020, 4, 2)
date2 = datetime.datetime(2020, 4, 12)
delta = datetime.timedelta(hours = 24)
dates = drange(date1, date2, delta)
 
y = np.arange(len(dates))
 
plt.plot_date(dates, y ** 2)
plt.title('matplotlib.pyplot.plot_date() function Example', fontweight ="bold")
plt.show()

Output:

Example #2:

Python3

# Implementation of matplotlib function
import datetime
import matplotlib.pyplot as plt
from matplotlib.dates import DayLocator, HourLocator, DateFormatter, drange
import numpy as np
 
date1 = datetime.datetime(2020, 4, 2)
date2 = datetime.datetime(2020, 4, 6)
delta = datetime.timedelta(hours = 6)
dates = drange(date1, date2, delta)
 
y = np.arange(len(dates))
 
fig, ax = plt.subplots()
ax.plot_date(dates, y ** 2, 'g')
 
ax.set_xlim(dates[0], dates[-1])
 
ax.xaxis.set_major_locator(DayLocator())
ax.xaxis.set_minor_locator(HourLocator(range(0, 25, 6)))
ax.xaxis.set_major_formatter(DateFormatter('% Y-% m-% d'))
 
ax.fmt_xdata = DateFormatter('% Y-% m-% d % H:% M:% S')
fig.autofmt_xdate()
plt.title('matplotlib.pyplot.plot_date() function Example', fontweight ="bold")
plt.show()