Showing entire X Axis Ticks in Graph

Question

I'm trying to have the tick labels of my Graph displayed fully, but I'm not getting the desired result, despite my efforts.

If I merely use autofmt_xdate(), the dates are correctly shown, but not for every data point plotted; however, if I force my x tick labels to be displayed by passing x by datetime objects to xtick(), It only seems to display the year.

    fig1 = plt.figure(1)
    # x is a list of datetime objects
    plt.title('Portfolio Instruments')
    plt.subplot(111)
    plt.plot(x, y)
    plt.xticks(fontsize='small')
    plt.yticks([i * 5 for i in range(0, 15)])
    fig1.autofmt_xdate()
    plt.show()

Graph passing x to plt.xticks():

Graph without passing x to plt.xticks()

Where's my mistake? I can't find it.

Question How do I plot all of my data points of x and format it to show the entire datetime object I'm passing the graph using autofmt_xdate()?

I have a list of datetime objects which I want to pass as the x values of my plot.

If you know the number of datapoints beforehand, or if there will always be the same amount of data you can set the xticks to be equal to a certain number. If there was a simpler example which gave you the same problem then it would be easier to give a more specific answer. — DavidG, Feb 29 '16 at 13:18
But that's what I'm doing already, afaik, when I pass list `x` to `xticks()` or not? I have a known number of data points. — deepbrook, Feb 29 '16 at 13:22
So what I thought was that `autofmt_xdate` sees the datetime objects passed to `xticks()` and converts them, just like it did before. This is not the case. The only difference is that I'm forcing the graph to show all x tick labels on the x axis. — deepbrook, Feb 29 '16 at 13:26
See my answer here for another option: https://stackoverflow.com/questions/39714724/pandas-plot-x-axis-tick-frequency-how-can-i-show-more-ticks/48401584#48401584 I wasn't sure if adding it here was o.k. due to cross-posting. Cheers — Cord Kaldemeyer, Jan 23 '18 at 12:23

score 1 · Answer 1 · answered Feb 29 '16 at 13:34

I'm pretty sure I had a similar problem, and the way I solved it was to use the following code:

def formatFig():
    date_formatter = DateFormatter('%H:%M:%S') #change the format here to whatever you like
    plt.gcf().autofmt_xdate()
    ax = plt.gca()
    ax.xaxis.set_major_formatter(date_formatter)
    max_xticks = 10      # sets the number of x ticks shown. Change this to number of data points you have
    xloc = plt.MaxNLocator(max_xticks)
    ax.xaxis.set_major_locator(xloc)

def makeFig():
    plt.plot(xList,yList,color='blue')    
    formatFig()

makeFig()
plt.show(block=True)

It is a pretty simple example but you should be able to transfer the formatfig() part to use in your code.

tmdavison · Accepted Answer · 2016-02-29T13:45:26.707

Pass the dates you want ticks at to xticks, and then set the major formatter for the x axis, using plt.gca().xaxis.set_major_formatter:

You can then use the DateFormatter from matplotlib.dates, and use a strftime format string to get the format in your question:

import matplotlib.dates as dates
fig1 = plt.figure(1)
# x is a list of datetime objects
plt.title('Portfolio Instruments')
plt.subplot(111)
plt.plot(x, y)

plt.xticks(x,fontsize='small') 
plt.gca().xaxis.set_major_formatter(dates.DateFormatter('%b %d %Y'))

plt.yticks([i * 5 for i in range(0, 15)])

fig1.autofmt_xdate()
plt.show()

Note: I created the data for the above plot using the code below, so x is just a list of datetime objects for each weekday in a month (i.e. without weekends).

import numpy as np
from datetime import datetime,timedelta

start = datetime(2016, 1, 1)
end = datetime(2016, 2, 1)
delta = timedelta(days=1)
d = start
weekend = set([5, 6])

x = []
while d <= end:
    if d.weekday() not in weekend:
        x.append(d)
    d += delta

y = np.random.rand(len(x))*70

Showing entire X Axis Ticks in Graph

2 Answers2