In dashboard, `plt.show()` show intermediate matplotlib output

[cderv]

---
title: "Reproducible Quarto Document"
format: 
  html: default
  dashboard: default
engine: jupyter
---

```{python}
#| echo: false
import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5, 10]
p = plt.boxplot(x)
plt.title("Test");
plt.show()
```

We get this in HTML

And this in dashboard

Suppressing plt.show() output is ok :

plt.show();

So it seems we don't consider output the same in Dashboard and HTML, and that supressing output with ; is required with matplotlib show()

If this is expected, we should probably document the difference. Though I am surprised - hence why I open the issue for future reference.

[stragu]

Another example below, This is for a .py source file rendered with quarto render dashboard.py.

It shows that the issue happens even without using plt.show(), and affects seaborn too. Same happens when editing e.g. axis labels with plt.xlabel() and plt.ylabel().

Workarounds are:

• suppressing the output of the last command, or
• assigning all commands to variables

Using following versions:

• quarto 1.6.39
• matplotlib 3.9.3
• seaborn 0.13.2
• python 3.11.10

# %% [markdown]
# ---
# title: "title and label outputs shown in dashboards"
# format: dashboard
# ---

# %% [markdown]
"""
## matplotlib only
"""

# %%
#| title: only matplotlib, no modification of title or labels
import matplotlib.pyplot as plt
x = [1, 2, 3, 4, 5, 10]
plt.boxplot(x)

# %%
#| title: "workaround: output suppressed by appending semicolon"
plt.boxplot(x);

# %%
#| title: only matlplotlib, with plt.title()
plt.boxplot(x)
plt.title("Test")

# %%
#| title: "workaround: output suppressed for last command"
plt.boxplot(x)
plt.title("Test");

# %%
#| title: "alternative workaround: assign each command to variables"
some_var = plt.boxplot(x)
some_var = plt.title("Test")

# %% [markdown]
"""
## seaborn
"""

# %%
#| title: seaborn on its own
import seaborn as sns
sns.boxplot(y = x)

# %%
#| title: seaborn + plt.title(), same issue
sns.boxplot(y = x)
plt.title("Test")

# %%
#| title: seaborn with its own set_title() method, same issue
sns.boxplot(y = x).set_title("Test")

# %%
#| title: workaround suppressing output works too for plt.title()
sns.boxplot(y = x)
plt.title("Test");

# %%
#| title: workaround suppressing output works too for set_title()
sns.boxplot(y = x).set_title("Test");