TypeError: 'GetAttrExpression' object is not callable with interval.ref()

[ghost]

Thanks for the wonderful library!

Using the previous version 4.2.2, everything works fine, but with 5.0.0, the following code produces the error shown:

interval = alt.selection_interval(encodings=["x"])
interval.ref()

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Cell In[10], line 2
      1 interval = alt.selection_interval(encodings=["x"])
----> 2 interval.ref()

TypeError: 'GetAttrExpression' object is not callable

[mattijn]

Thanks for the report @tkyoma!

In Altair version 4.2.2 the .ref() did return a dictionary, but from Altair version 5 the alt.selection_interval() returns a Parameter object and not a Selection object.

Can you elaborate a little bit more in what way you are using this syntax? I'm not yet sure if this a bug or a breaking change. Would it for example be possible to use interval.to_dict() instead?

[EtienneT]

I got the exact same problem today.

I installed altair 5.0.0, coded some graphs, then installed streamlit which requires altair 4. I later realized that the code was not working anymore and uninstalled streamlit and reinstalled altair 5, but the .ref() error was still occurring even though I restarted my notebook kernel, restarted jupyter to make sure I was using the latest version. alt.version returns 5.0.0 too.

I can reproduce the problem by using this example from the docs:

import altair as alt
from vega_datasets import data

weather = data.seattle_weather()

interval = alt.selection_interval(encodings=['x'])

base = alt.Chart(weather).mark_rule(size=2).encode(
    x='date:T',
    y='temp_min:Q',
    y2='temp_max:Q',
    color='weather:N'
)

chart = base.encode(
    x=alt.X('date:T', scale=alt.Scale(domain=interval.ref()))
).properties(
    width=800,
    height=300
)

view = base.add_selection(
    interval
).properties(
    width=800,
    height=50,
)

chart & view

I am getting the following error:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
Input In [1], in <cell line: 15>()
      6 interval = alt.selection_interval(encodings=['x'])
      8 base = alt.Chart(weather).mark_rule(size=2).encode(
      9     x='date:T',
     10     y='temp_min:Q',
     11     y2='temp_max:Q',
     12     color='weather:N'
     13 )
     15 chart = base.encode(
---> 16     x=alt.X('date:T', scale=alt.Scale(domain=interval.ref()))
     17 ).properties(
     18     width=800,
     19     height=300
     20 )
     22 view = base.add_selection(
     23     interval
     24 ).properties(
     25     width=800,
     26     height=50,
     27 )
     29 chart & view

TypeError: 'GetAttrExpression' object is not callable

[joelostblom]

@EtienneT Does your example work if you remove the .ref part and just use domain=interval? And could you give a link to the where in the docs that example is so that we can update it?

[EtienneT]

Here is the documentation link:
https://altair-viz.github.io/altair-tutorial/notebooks/06-Selections.html#binding-scales-to-other-domains

On my main conda environment, if I remove the call to .ref(), I get the following error:

C:\Users\etrem\anaconda3\envs\fastai\lib\site-packages\altair\utils\deprecation.py:65: AltairDeprecationWarning: 'add_selection' is deprecated. Use 'add_params' instead.
  warnings.warn(message, AltairDeprecationWarning, stacklevel=1)
Javascript Error: e.map is not a function
This usually means there's a typo in your chart specification. See the javascript console for the full traceback.

Even though I am using version 5.0.0.

But then I created a completely fresh environment, tried it without the .ref() call and it works. Something got corrupted in my current environment.

[EtienneT]

Can we do the same x-axis selection in altair 4 (to work in streamlit) which changes the scale of the X axis?

Thanks,