FacetGrid change titles

Question

I am trying to create a FacetGrid in Seaborn

My code is currently:

g = sns.FacetGrid(df_reduced, col="ActualExternal", margin_titles=True)
bins = np.linspace(0, 100, 20)
g.map(plt.hist, "ActualDepth", color="steelblue", bins=bins, width=4.5)

This gives my the Figure

Now, instead of "ActualExternal = 0.0" and "ActualExternal = 1.0", I would like the titles "Internal" and "External"

And, instead of "ActualDepth" I would like the xlabel to say "Percentage Depth"

Finally, I would like to add a ylabel of "Number of Defects".

Headmistress

As per seaborn.FacetGrid, it's better to directly use figure-level functions like g = sns.displot(data=df_reduced, kind='hist', ...) instead of sns.FacetGrid. The answers still work for this. – Neill

Answer 1

You can access the axes of a FacetGrid (g = sns.FacetGrid(...)) via g.axes. With that you are free to use any matplotlib method you like to tweak the plot.

Change titles:

axes = g.axes.flatten()
axes[0].set_title("Internal")
axes[1].set_title("External")

Change labels:

axes = g.axes.flatten()
axes[0].set_ylabel("Number of Defects")
for ax in axes:
    ax.set_xlabel("Percentage Depth")

Note that I prefer those above the FacetGrid's internal g.set_axis_labels and set_titles methods, because it makes it more obvious which axes is to be labelled.

Mincing

@Mincing Use the g.set_axis_labels method instead of modifying the label attributes on the axes directly. – Boxfish

Answer 2

Although you can iterate through the axes and set the titles individually using matplotlib commands, it is cleaner to use seaborn's built-in tools to control the title. For example:

# Add a column of appropriate labels
df_reduced['measure'] = df_reduced['ActualExternal'].replace({0: 'Internal',
                                                              1: 'External'}

g = sns.FacetGrid(df_reduced, col="measure", margin_titles=True)
g.map(plt.hist, "ActualDepth", color="steelblue", bins=bins, width=4.5)

# Adjust title and axis labels directly
g.set_titles("{col_name}")  # use this argument literally
g.set_axis_labels(x_var="Percentage Depth", y_var="Number of Defects")

This has the benefit of not needing modification regardless of whether you have 1D or 2D facets.

Manvil

Also, in order to escape the curly braces you need to double it. See: graph.set_titles(template = "$\alpha_{{ {row_name} }}$"). – Calf

Answer 3

Another way to set multiple titles could be:

titles = ['Internal','External']

for ax, title in zip(g.axes.flatten(),titles):
    ax.set_title(title)

Arboriculture