When either the x or y parameters to the Plotly Express constructor are passed lists of values, they are mutated such that values are converted to string.
Expected behaviour: Plotly Express should not mutate objects supplied as arguments by the user.
Minimal example (tested on Plotly 5.13.1 and master branch):
from random import randrange
import pandas as pd
import plotly.express as px
cols, rows = list(range(3)), list(range(10))
print(cols)
df = pd.DataFrame({col: [randrange(100) for _row in rows] for col in cols})
px.bar(df, y=cols, barmode="group")
print(cols)
Before the px.bar() call, cols has the value [1, 2, 3] and afterwards it is ["1", "2", "3"]. The same behaviour occurs for the x param and also when using other plotting functions than pxbar() (I tried px.histogram()).
I did some poking around, and can see that in the function build_dataframe in plotly/express/_core.py, the some of the fields in the user supplied args have copies made (which would fix this issue), but that is only applied to args found in the array_attrables list, which is ["dimensions", "custom_data", "hover_data", "path", "wide_variable"], which does not include x and y.
When either the
xoryparameters to the Plotly Express constructor are passed lists of values, they are mutated such that values are converted to string.Expected behaviour: Plotly Express should not mutate objects supplied as arguments by the user.
Minimal example (tested on Plotly 5.13.1 and master branch):
Before the
px.bar()call,colshas the value[1, 2, 3]and afterwards it is["1", "2", "3"]. The same behaviour occurs for thexparam and also when using other plotting functions thanpxbar()(I triedpx.histogram()).I did some poking around, and can see that in the function
build_dataframeinplotly/express/_core.py, the some of the fields in the user supplied args have copies made (which would fix this issue), but that is only applied to args found in thearray_attrableslist, which is["dimensions", "custom_data", "hover_data", "path", "wide_variable"], which does not includexandy.