How can I add grid lines to a catplot in seaborn?

Question

How can I add grid lines (vertically and horizontally) to a seaborn catplot? I found a possibility to do that on a boxplot, but I have multiple facets and therefore need a catplot instead. And in contrast to this other answer, catplot does not allow an ax argument.

This code is borrowed from here.

import seaborn as sns
sns.set(style="ticks")
exercise = sns.load_dataset("exercise")
g = sns.catplot(x="time", y="pulse", hue="kind", data=exercise)
plt.show()

Any ideas? Thank you!

EDIT: The provided answer is working, but for faceted plots, only the last plot inherits the grid.

import seaborn as sns
sns.set(style="ticks")
exercise = sns.load_dataset("exercise")
g = sns.catplot(x="time", y="pulse", hue="kind", col="diet", data=exercise)
plt.grid()
plt.show()

Can someone explain to me why and how to fix it?

Answer 1

You can set the grid over seaborn plots in two ways:

1. plt.grid() method:

You need to use the grid method inside matplotlib.pyplot. You can do that like so:

import seaborn as sns
import matplotlib.pyplot as plt

sns.set(style="ticks")
exercise = sns.load_dataset("exercise")
g = sns.catplot(x="time", y="pulse", hue="kind", data=exercise)
plt.grid()  #just add this
plt.show()

Which results in this graph:

2. sns.set_style() method

You can also use sns.set_style which will enable grid over all subplots in any given FacetGrid. You can do that like so:

import seaborn as sns
import matplotlib.pyplot as plt


sns.set(style="ticks")
exercise = sns.load_dataset("exercise")
sns.set_style("darkgrid")
g = sns.catplot(x="time", y="pulse", hue="kind", col="diet", data=exercise)
plt.show()

Which returns this graph:

Answer 2

Came into this question looking for a way of adding grids to a FacetGrid plot, without using the "whitegrid" style. After trying many solutions, I found that in faceted plots one has to add {'axes.grid' : True} to the set_style function:

import seaborn as sns
sns.set_style("ticks",{'axes.grid' : True})
g = sns.FacetGrid(df, col="column_variable",col_wrap=4, height=2.3)