Altair Ridgeline doesn't create a plot with nominal groups
问题 I try to create a Ridgeline plot in altair. Let's assume my dataframe consists of str and float columns: a object b float64 dtype: object with values like a b 0 25 2303.0 1 29 2676.0 2 18 2983.0 3 16 1489.0 4 21 3468.0 I used code from Altair gallery to create my chart: https://altair-viz.github.io/gallery/ridgeline_plot.html. My code with changed data and column names: import pandas as np import numpy as np source = pd.DataFrame(columns=list('ab')) source['a'] = np.random.randint(0,17,size