在python matplotlib中旋转轴文本

I can’t figure out how to rotate the text on the X Axis. Its a time stamp, so as the number of samples increase, they get closer and closer until they overlap. I’d like to rotate the text 90 degrees so as the samples get closer together, they aren’t overlapping.

Below is what I have, it works fine with the exception that I can’t figure out how to rotate the X axis text.

import sys

import matplotlib
matplotlib.use('Agg')
import matplotlib.pyplot as plt
import datetime

font = {'family' : 'normal',
        'weight' : 'bold',
        'size'   : 8}

matplotlib.rc('font', **font)

values = open('stats.csv', 'r').readlines()

time = [datetime.datetime.fromtimestamp(float(i.split(',')[0].strip())) for i in values[1:]]
delay = [float(i.split(',')[1].strip()) for i in values[1:]]

plt.plot(time, delay)
plt.grid(b='on')

plt.savefig('test.png')

This works for me:

plt.xticks(rotation=90)

Easy way

As described here, there is an existing method in the matplotlib.pyplot figure class that automatically rotates dates appropriately for you figure.

You can call it after you plot your data (i.e.ax.plot(dates,ydata) :

fig.autofmt_xdate()

If you need to format the labels further, checkout the above link.

Non-datetime objects

As per languitar‘s comment, the method I suggested for non-datetime xticks would not update correctly when zooming, etc. If it’s not a datetime object used as your x-axis data, you should follow Tommy‘s answer:

for tick in ax.get_xticklabels():
    tick.set_rotation(45)

Many “correct” answers here but I’ll add one more since I think some details are left out of several. The OP asked for 90 degree rotation but I’ll change to 45 degrees because when you use an angle that isn’t zero or 90, you should change the horizontal alignment as well; otherwise your labels will be off-center and a bit misleading (and I’m guessing many people who come here want to rotate axes to something other than 90).

Easiest / Least Code

Option 1

plt.xticks(rotation=45, ha='right')

As mentioned previously, that may not be desirable if you’d rather take the Object Oriented approach.

Option 2

Another fast way (it’s intended for date objects but seems to work on any label; doubt this is recommended though):

fig.autofmt_xdate(rotation=45)

fig you would usually get from:

• fig = plt.figure()
• fig, ax = plt.subplots()
• fig = ax.figure

Object-Oriented / Dealing directly with ax

Option 3a

If you have the list of labels:

labels = ['One', 'Two', 'Three']
ax.set_xticklabels(labels, rotation=45, ha='right')

Option 3b

If you want to get the list of labels from the current plot:

# Unfortunately you need to draw your figure first to assign the labels,
# otherwise get_xticklabels() will return empty strings.
plt.draw()
ax.set_xticklabels(ax.get_xticklabels(), rotation=45, ha='right')

Option 4

Similar to above, but loop through manually instead.

for label in ax.get_xticklabels():
  label.set_rotation(45)
  label.set_ha('right')

Option 5

We still use pyplot (as plt) here but it’s object-oriented because we’re changing the property of a specific ax object.

plt.setp(ax.get_xticklabels(), rotation=45, ha='right')

Option 6

This option is simple, but AFAIK you can’t set label horizontal align this way so another option might be better if your angle is not 90.

ax.tick_params(axis='x', labelrotation=45)

Edit: There’s discussion of this exact “bug” and a fix is potentially slated for v3.2.0: https://github.com/matplotlib/matplotlib/issues/13774

Try pyplot.setp. I think you could do something like this:

x = range(len(time))
plt.xticks(x,  time)
locs, labels = plt.xticks()
plt.setp(labels, rotation=90)
plt.plot(x, delay)

Appart from

plt.xticks(rotation=90)

this is also possible:

plt.xticks(rotation='vertical')

I came up with a similar example. Again, the rotation keyword is.. well, it’s key.

from pylab import *
fig = figure()
ax = fig.add_subplot(111)
ax.bar( [0,1,2], [1,3,5] )
ax.set_xticks( [ 0.5, 1.5, 2.5 ] )
ax.set_xticklabels( ['tom','dick','harry'], rotation=45 ) ;

My answer is inspired by cjohnson318’s answer, but I didn’t want to supply a hardcoded list of labels; I wanted to rotate the existing labels:

for tick in ax.get_xticklabels():
    tick.set_rotation(45)

If using plt:

plt.xticks(rotation=90)

In case of using pandas or seaborn to plot, assuming ax as axes for the plot:

ax.set_xticklabels(ax.get_xticklabels(), rotation=90)

Another way of doing the above:

for tick in ax.get_xticklabels():
    tick.set_rotation(45)

If you want to apply rotation on the axes object, the easiest way is using tick_params. For example.

ax.tick_params(axis='x', labelrotation=90)

Matplotlib documentation reference here.

This is useful when you have an array of axes as returned by plt.subplots, and it is more convenient than using set_xticks because in that case you need to also set the tick labels, and also more convenient that those that iterate over the ticks (for obvious reasons)

import pylab as pl
pl.xticks(rotation = 90)

It will depend on what are you plotting.

import matplotlib.pyplot as plt

 x=['long_text_for_a_label_a',
    'long_text_for_a_label_b',
    'long_text_for_a_label_c']
y=[1,2,3]
myplot = plt.plot(x,y)
for item in myplot.axes.get_xticklabels():
    item.set_rotation(90)

For pandas and seaborn that give you an Axes object:

df = pd.DataFrame(x,y)
#pandas
myplot = df.plot.bar()
#seaborn 
myplotsns =sns.barplot(y='0',  x=df.index, data=df)
# you can get xticklabels without .axes cause the object are already a 
# isntance of it
for item in myplot.get_xticklabels():
    item.set_rotation(90)

If you need to rotate labels you may need change the font size too, you can use font_scale=1.0 to do that.

To rotate the x-axis label to 90 degrees

for tick in ax.get_xticklabels():
    tick.set_rotation(45)

The simplest solution is to use:

plt.xticks(rotation=XX)

but also

# Tweak spacing to prevent clipping of tick-labels
plt.subplots_adjust(bottom=X.XX)

e.g for dates I used rotation=45 and bottom=0.20 but you can do some test for your data