Matplotlib pyplot - tick control and display date
Mine has matplotlib pyplot
too many xticks
- it shows every year and month over a 15 year period, for example. "2001-01", but I want the x-axis to show the year (eg 2001).
The output will be a line graph where the x-axis shows dates and the y-axis shows the sale and rental prices.
# Defining the variables
ts1 = prices['Month'] # eg. "2001-01" and so on
ts2 = prices['Sale']
ts3 = prices['Rent']
# Reading '2001-01' as year and month
ts1 = [dt.datetime.strptime(d,'%Y-%m').date() for d in ts1]
plt.figure(figsize=(13, 9))
# Below is where it goes wrong. I don't know how to set xticks to show each year.
plt.xticks(ts1, rotation='vertical')
plt.xlabel('Year')
plt.ylabel('Price')
plt.plot(ts1, ts2, 'r-', ts1, ts3, 'b.-')
plt.gcf().autofmt_xdate()
plt.show()
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You can do this with plt.xticks
.
As an example, here I have set the xticks frequency to display every three indices. In your case, you probably want to do this every twelve indices.
import numpy as np
import matplotlib.pyplot as plt
x = np.arange(10)
y = np.random.randn(10)
plt.plot(x,y)
plt.xticks(np.arange(min(x), max(x)+1, 3))
plt.show()
In your case, since you are using dates, you can replace the second argument with the last line above with something like ts1[0::12]
that will select every 12th item from, ts1
or np.arange(0, len(dates), 12)
that will select every 12th index corresponding to the ticks you want show.
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Try to remove the function call entirely plt.xticks
. matplotlib will use a function AutoDateLocator
to find the optimal tick locations.
Alternatively, if the default is multiple months, which you don't want, you can use matplotlib.dates.YearLocator
that will force the ticks to be years only.
You can set the locator as shown below in a short example:
import matplotlib.pyplot as plt
import matplotlib.dates as mdate
import numpy as np
import datetime as dt
x = [dt.datetime.utcnow() + dt.timedelta(days=i) for i in range(1000)]
y = range(len(x))
plt.plot(x, y)
locator = mdate.YearLocator()
plt.gca().xaxis.set_major_locator(locator)
plt.gcf().autofmt_xdate()
plt.show()
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