Error on using add_vline with text annotation for data with date-time x axis

Hi, I am trying to use the library for a simple visualisation for the first time, and I stumbled upon supposedly a bug trying to draw a vertical line with text annotation on a graph with a date-time x axis.

import plotly.express as px
df = px.data.stocks(indexed=True)
fig = px.line(df)
fig.add_vline(x="2018-09-24", annotation_text="test" )
fig.show()

I get the following error message:

TypeError: unsupported operand type(s) for +: 'int' and 'str'

Could anyone please help me confirm that it is indeed a bug, my version is ‘4.14.1’ ? Thank you.

[awrobel1]

Hi @MR0205,

If you’re looking for a temporary workaround, you can get the annotation to work by converting your x value into milliseconds since epoch as follows:

import plotly.express as px
import datetime
df = px.data.stocks(indexed=True)
fig = px.line(df)
fig.add_vline(x=datetime.datetime.strptime("2018-09-24", "%Y-%m-%d").timestamp() * 1000, annotation_text="test" )
fig.show()

[tomshaffner]

The above suggestion from @awrobel1 was great for me. In my case I simplified a tad with x=datetime.datetime(2021,5,27).timestamp() * 1000. No need to convert from a string first in this case.