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.

Solution 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])

Solution 2:

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

Solution 3:

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

• if rotation=45, then add rotation_mode='anchor'
• otherwise add a ScaledTranslation

rotation_mode='anchor'

If the rotation angle is roughly 45 deg, then setting rotation_mode='anchor' is simplest:

x = xticks = np.arange(10)
xticklabels = (f'xticklabel {tick}' for tick in xticks)

fig, ax = plt.subplots()
ax.bar(x, x - 4.5)
ax.set_xticks(xticks)

# since rotation=45, anchor the rotation to fix label/tick alignment
ax.set_xticklabels(xticklabels, rotation=45, ha='right', rotation_mode='anchor')

However this doesn't work well for other angles like 70 deg (see left), in which case we need to apply a ScaledTranslation (see right):

ScaledTranslation

If the rotation angle is more extreme or you just want more fine-grained control, then apply a ScaledTranslation as described in how to move a tick's label in matplotlib:

...
ax.set_xticklabels(xticklabels, rotation=70, ha='right')

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

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

Solution 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".

Solution 5:

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

plt.xticks(rotation=45)