Matplotlib.dates.datestr2num() in Python

Matplotlib is an amazing visualization library in Python for 2D plots of arrays. Matplotlib is a multi-platform data visualization library built on NumPy arrays and designed to work with the broader SciPy stack.

matplotlib.dates.datestr2num()

The matplotlib.dates.datestr2num() function is used to convert a date string to a datenum by the uses of dateutil.parser.parser().

Syntax: matplotlib.dates.datestr2num(d, default=None)

Parameters:

d: It is a string or a sequence of strings representing the dates.
default: This is an optional parameter that is a datetime instance. This is used when fields are not present in d, as a default.

Example 1:

from datetime import datetime 
import matplotlib.pyplot as plt 
from matplotlib.dates import ( 
    DateFormatter, AutoDateLocator, AutoDateFormatter, datestr2num 
) 
  
  
days = [ 
    '30/01/2019', 
    '31/01/2019',  
    '01/02/2019', 
    '02/02/2019',  
    '03/02/2019',  
    '04/02/2019'
] 
data1 = [2, 5, 13, 6, 11, 7] 
data2 = [6, 3, 10, 3, 6, 5] 
  
z = datestr2num([ 
    datetime.strptime(day, '%d/%m/%Y').strftime('%m/%d/%Y') 
    for day in days 
]) 
  
r = 0.25
  
figure = plt.figure(figsize =(8, 4)) 
axes = figure.add_subplot(111) 
  
axes.bar(z - r, data1, width = 2 * r, 
         color ='g', align ='center', 
         tick_label = day) 
  
axes.bar(z + r, data2, width = 2 * r, 
         color ='y', align ='center',  
         tick_label = day) 
  
axes.xaxis_date() 
axes.xaxis.set_major_locator( 
    AutoDateLocator(minticks = 3, interval_multiples = False)) 
  
axes.xaxis.set_major_formatter(DateFormatter("%d/%m/%y")) 
  
plt.show() 

Output:

Example 2:

import matplotlib 
import matplotlib.pyplot as plt 
import matplotlib.dates 
  
  
dates =  ['1920-05-06',  
          '1920-05-07',  
          '1947-05-08',  
          '1920-05-09'] 
  
converted_dates = matplotlib.dates.datestr2num(dates) 
  
x_axis = (converted_dates) 
y_axis = range(0, 4) 
  
plt.plot_date( x_axis, y_axis, '-' ) 
  
plt.show() 

Output:

My Personal Notes

matplotlib.dates.datestr2num()

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