pyplot, why isn't the x-axis showing?

Question

I\'m trying to plot some values against date. However, unfortunately i\'m not getting any values in the x Axis. I feel that this could be due to two factors:

1. The v

Answer 1

If you want to control the major and minor ticks locations and formats you will need to use date tickers. Here is a function I regularly use for plot time series that span multiple months:

def format_xaxis(fig):
     # here I am setting the major ticks to each decade
     # Change to something appropriate for your data
     major= dates.MonthLocator(bymonthday=1)

     #Here I am setting each minor ticks to mid-decade 
     # Change to something appropriate for your data    
     minor=dates.MonthLocator(bymonthday=15)

     #Here I am setting each major ticks and minor tick formatting
     # Change to something appropriate for your data 
     #look at http://strftime.org/ for other options
     majorfmt = dates.DateFormatter('%B')
     minorfmt = dates.DateFormatter('%d')

     # Set the locators and formats for all of the subplots axes
     [i.xaxis.set_major_locator(major) for i in fig.axes]
     [i.xaxis.set_minor_locator(minor) for i in fig.axes]
     [i.xaxis.set_major_formatter(majorfmt) for i in fig.axes]
     [i.xaxis.set_minor_formatter(minorfmt) for i in fig.axes]

     # Here I am offsetting the major ticks down so they dont overlap with minor tick lables
     [i.get_xaxis().set_tick_params(which='major', pad=15) for i in fig.axes]

     #make them look nice
     for t in fig.axes:
         for tick in t.xaxis.get_major_ticks():
             tick.label1.set_horizontalalignment('center')
         for label in t.get_xmajorticklabels() :
             label.set_rotation(0)
             label.set_weight('bold')
         for label in t.xaxis.get_minorticklabels():
             label.set_fontsize('small')   

You can swap out dates.MonthLocator for any locator appropriate for your data. Just look at the link I provided.

A little example:

import pandas as pd
import matplotlib.pyplot as plt
import matplotlib.dates as dates
import numpy as np

df = pd.DataFrame({'Date':pd.date_range(start = '2015-01-01', end = '2015-05-01'), 'TotalDeepSleep':np.random.randint(0,140,size=121)})


fig,ax = plt.subplots()
ax.plot_date(df['Date'], df['TotalDeepSleep'])

format_xaxis(fig)