Aligning rotated xticklabels with their respective xticks

Check the x axis of the figure below. How can I move the labels a bit to the left so that they align with their respective ticks?

I’m rotating the labels using:

ax.set_xticks(xlabels_positions)
ax.set_xticklabels(xlabels, rotation=45)

But, as you can see, the rotation is centered on the middle of the text labels. Which makes it look like they are shifted to the right.

I’ve tried using this instead:

ax.set_xticklabels(xlabels, rotation=45, rotation_mode="anchor")

… but it doesn’t do what I wished for. And "anchor" seems to be the only value allowed for the rotation_mode parameter.

Answers:

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Method 1

You can set the horizontal alignment of ticklabels, see the example below. If you imagine a rectangular box around the rotated label, which side of the rectangle do you want to be aligned with the tickpoint?

Given your description, you want: ha=’right’

n=5

x = np.arange(n)
y = np.sin(np.linspace(-3,3,n))
xlabels = ['Ticklabel %i' % i for i in range(n)]

fig, axs = plt.subplots(1,3, figsize=(12,3))

ha = ['right', 'center', 'left']

for n, ax in enumerate(axs):
    ax.plot(x,y, 'o-')
    ax.set_title(ha[n])
    ax.set_xticks(x)
    ax.set_xticklabels(xlabels, rotation=40, ha=ha[n])

Method 2

ha='right' is not enough to visually align labels with ticks:

• For rotation=45, use both ha='right' and rotation_mode='anchor'
• For other angles, use a ScaledTranslation() instead

rotation_mode='anchor'

If the rotation angle is roughly 45°, combine ha='right' with rotation_mode='anchor':

ax.set_xticks(ticks)
ax.set_xticklabels(labels, rotation=45, ha='right', rotation_mode='anchor')

Or in matplotlib 3.5.0+, set ticks and labels at once:

ax.set_xticks(ticks, labels, rotation=45, ha='right', rotation_mode='anchor')

ScaledTranslation()

If the rotation angle is more extreme (e.g., 70°) or you just want more fine-grained control, anchoring won’t work well. Instead, apply a linear transform:

ax.set_xticks(ticks)
ax.set_xticklabels(labels, rotation=70)

# create -5pt offset in x direction
from matplotlib.transforms import ScaledTranslation
dx, dy = -5, 0
offset = ScaledTranslation(dx / fig.dpi, dy / fig.dpi, fig.dpi_scale_trans)

# apply offset to all xticklabels
for label in ax.xaxis.get_majorticklabels():
    label.set_transform(label.get_transform() + offset)

Method 3

Rotating the labels is certainly possible. Note though that doing so reduces the readability of the text. One alternative is to alternate label positions using a code like this:

import numpy as np
n=5

x = np.arange(n)
y = np.sin(np.linspace(-3,3,n))
xlabels = ['Long ticklabel %i' % i for i in range(n)]


fig, ax = plt.subplots()
ax.plot(x,y, 'o-')
ax.set_xticks(x)
labels = ax.set_xticklabels(xlabels)
for i, label in enumerate(labels):
    label.set_y(label.get_position()[1] - (i % 2) * 0.075)

For more background and alternatives, see this post on my blog

Method 4

An easy, loop-free alternative is to use the horizontalalignment Text property as a keyword argument to xticks[1]. In the below, at the commented line, I’ve forced the xticks alignment to be “right”.

n=5
x = np.arange(n)
y = np.sin(np.linspace(-3,3,n))
xlabels = ['Long ticklabel %i' % i for i in range(n)]
fig, ax = plt.subplots()
ax.plot(x,y, 'o-')

plt.xticks(
        [0,1,2,3,4],
        ["this label extends way past the figure's left boundary",
        "bad motorfinger", "green", "in the age of octopus diplomacy", "x"], 
        rotation=45,
        horizontalalignment="right")    # here
plt.show()

(yticks already aligns the right edge with the tick by default, but for xticks the default appears to be “center”.)
[1] You find that described in the xticks documentation if you search for the phrase “Text properties”.

Method 5

I am clearly late but there is an official example which uses

plt.setp(ax.get_xticklabels(), rotation=45, ha="right", rotation_mode="anchor")

to rotate the labels while keeping them correctly aligned with the ticks, which is both clean and easy.

See: https://matplotlib.org/stable/gallery/images_contours_and_fields/image_annotated_heatmap.html

Method 6

If you dont want to modify the xtick labels, you can just use:

plt.xticks(rotation=45)

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0