Using one label for a facet grid not documented

[mcp292]

Using one label for an entire facet grid is not documented in Adjusting Axis Labels.

How can I make this plot only use one y-label?

MWE

import pandas as pd
import altair as alt


data = [{"P": "HD", "T": 0,  "C":100, "Max": 1},
        {"P": "HD", "T": 0,  "C":400, "Max": 3},
        {"P": "HD", "T": 0,  "C":800, "Max": 0},
        {"P": "HD", "T": 23, "C":100, "Max": 2},
        {"P": "HD", "T": 23, "C":400, "Max": 1},
        {"P": "HD", "T": 23, "C":800, "Max": 1},
        {"P": "HD", "T": 80, "C":100, "Max": 7},
        {"P": "HD", "T": 80, "C":400, "Max": 2},
        {"P": "HD", "T": 80, "C":800, "Max": 1},
        {"P": "LD", "T": 0,  "C":100, "Max": 1},
        {"P": "LD", "T": 0,  "C":400, "Max": 2},
        {"P": "LD", "T": 0,  "C":800, "Max": 7},
        {"P": "LD", "T": 23, "C":100, "Max": 7},
        {"P": "LD", "T": 23, "C":400, "Max": 1},
        {"P": "LD", "T": 23, "C":800, "Max": 0},
        {"P": "LD", "T": 80, "C":100, "Max": 2},
        {"P": "LD", "T": 80, "C":400, "Max": 0},
        {"P": "LD", "T": 80, "C":800, "Max": 1}]

df = pd.DataFrame(data)

chart = alt.Chart(df).mark_bar().encode(
    x="P:N",
    y=alt.Y("Max:Q", title="Maximum Long Word Observed (units)"),
    color="P:N",
    row="T:N",
    column="C:N"
).properties(width=100, height=100)

     P   T    C  Max
0   HD   0  100    1
1   HD   0  400    3
2   HD   0  800    0
3   HD  23  100    2
4   HD  23  400    1
5   HD  23  800    1
6   HD  80  100    7
7   HD  80  400    2
8   HD  80  800    1
9   LD   0  100    1
10  LD   0  400    2
11  LD   0  800    7
12  LD  23  100    7
13  LD  23  400    1
14  LD  23  800    0
15  LD  80  100    2
16  LD  80  400    0
17  LD  80  800    1

[mcp292]

I will put a $10 bounty on this!

[jakevdp]

In general you'll have better luck getting questions answered at https://github.com/altair-viz/altair/discussions or https://stackoverflow.com/questions/tagged/altair

[mcp292]

Awesome! That's what I was looking for here and here. Will pursue in those channels, but if you want to make a quick ten bucks...

I leave it to you as to whether or not to close this issue. It would be great information to have in that section.

[mcp292]

vega/altair#2666 (reply in thread)

It is not documented that you can pass an iterable to either header or title!