I am plotting with seaborn a series of boxplots with
sns.boxplot(full_array)
where full_array contains 200 arrays.
Therefore,
The seaborn boxplot uses a FixedLocator and a FixedFormatter, i.e.
print ax.xaxis.get_major_locator()
print ax.xaxis.get_major_formatter()
prints
<matplotlib.ticker.FixedLocator object at 0x000000001FE0D668>
<matplotlib.ticker.FixedFormatter object at 0x000000001FD67B00>
It's therefore not sufficient to set the locator to a MultipleLocator since the ticks' values would still be set by the fixed formatter.
Instead you would want to set a ScalarFormatter, which sets the ticklabels to correspond to the numbers at their position.
import matplotlib.pyplot as plt
import matplotlib.ticker as ticker
import seaborn.apionly as sns
import numpy as np
ax = sns.boxplot(data = np.random.rand(20,30))
ax.xaxis.set_major_locator(ticker.MultipleLocator(5))
ax.xaxis.set_major_formatter(ticker.ScalarFormatter())
plt.show()