Question: I am attempting to create a repeated graph in altair.

Here is my code: 

```
x = alt.Chart(data).mark_bar().encode(
    alt.X(alt.repeat("row"), type='quantitative'),
    alt.Y(alt.repeat("column"), type='quantitative')
).repeat(
row= ['country'],
column=['alcohol_use', 'drug_use', 'high_meat', 'low_exercise', 'smoking'])

```

When I run it, it just shows graphs with axes and nothing else. What could be wrong?

Answer: 
If you get empty graphs in a repeat chart, it usually means one of two things:

1. your data is not accessible by the frontend. This can happen, for example, if you pass your data as a URL and the URL has a typo.
2. the column names used in row/column are mis-typed.

As an example of the second issue, consider this chart from [Altair's documentation](https://altair-viz.github.io/user_guide/compound_charts.html#repeated-charts):

```
import altair as alt
from vega_datasets import data
iris = data.iris.url

alt.Chart(iris).mark_point().encode(
    alt.X(alt.repeat("column"), type='quantitative'),
    alt.Y(alt.repeat("row"), type='quantitative'),
    color='species:N'
).properties(
    width=200,
    height=200
).repeat(
    row=['petalLength', 'petalWidth'],
    column=['sepalLength', 'sepalwidth']
).interactive()

```

[![enter image description here](https://i.stack.imgur.com/pNIpe.png)](https://i.stack.imgur.com/pNIpe.png)

Now let's see what happens if we mis-spell the column names (here our "mis-spelling" involves changing an uppercase character to lowercase):

```
alt.Chart(iris).mark_point().encode(
    alt.X(alt.repeat("column"), type='quantitative'),
    alt.Y(alt.repeat("row"), type='quantitative'),
    color='species:N'
).properties(
    width=200,
    height=200
).repeat(
    row=['petallength', 'petalwidth'],
    column=['sepallength', 'sepalwidth']
).interactive()

```

[![enter image description here](https://i.stack.imgur.com/S6yEK.png)](https://i.stack.imgur.com/S6yEK.png)

Make certain that you aren't mis-spelling the column names: common issues are upper vs. lower case, special characters, and spaces at the beginning or end of the column name strings.
Turns out I needed to switch `alt.X(alt.repeat("row"), type='quantitative'),` to 
`alt.X(alt.repeat("row"), type='ordinal'),` because the row data is country names.