break_width Parameter in Datetime Scales

In datetime scales, the break_width parameter accepts a string specifying the interval between breaks, e.g., “2 weeks”, “3 months”, “12 hours”.

import pandas as pd
from datetime import datetime
from lets_plot import *

LetsPlot.setup_html()

economics_url = 'https://raw.githubusercontent.com/JetBrains/lets-plot-docs/master/data/economics.csv'
economics = pd.read_csv(economics_url)
economics['date'] = pd.to_datetime(economics['date'])
start = datetime(2007, 1, 1)
end = datetime(2013, 1, 1)
economics = economics.loc[economics['date'].between(start, end)]
economics.head()

	Unnamed: 0	date	pce	pop	psavert	uempmed	unemploy
474	475	2007-01-01	9516.3	300574.0	3.7	8.3	7116
475	476	2007-02-01	9546.8	300802.0	4.1	8.5	6927
476	477	2007-03-01	9585.1	301021.0	4.4	9.1	6731
477	478	2007-04-01	9615.7	301254.0	4.2	8.6	6850
478	479	2007-05-01	9651.3	301483.0	4.0	8.2	6766

# a datetime scale with auto-selected breaks
( 
  ggplot(mapping=aes('date', 'unemploy'))
    + geom_line(data=economics, size=5, alpha=0.5, color='teal')
    + theme_classic()
    + ggsize(800, 300)
) 

( 
  ggplot(mapping=aes('date', 'unemploy'))
    + geom_line(data=economics, size=5, alpha=0.5, color='teal')
    + scale_x_datetime(
        break_width='3 months',       # <-- breaks every 3 months
        format="%b '%y")
    + theme_classic()
    + ggsize(800, 300)
)