how can i create subplots with plotly express?

I was struggling to find a response on this as well so I ended up having to create my own solution (see my full breakdown here: How To Create Subplots Using Plotly Express)

Essentially make_subplots() takes in plot traces to make the subplots instead of figure objects like that which Express returns. So what you can do is, after creating your figures in Express, is break apart the Express figure objects into their traces and then re-assemble their traces into subplots.

Code:

import dash_core_components as dcc
import plotly.express as px
import plotly.subplots as sp


# Create figures in Express
figure1 = px.line(my_df)
figure2 = px.bar(my_df)

# For as many traces that exist per Express figure, get the traces from each plot and store them in an array.
# This is essentially breaking down the Express fig into it's traces
figure1_traces = []
figure2_traces = []
for trace in range(len(figure1["data"])):
    figure1_traces.append(figure1["data"][trace])
for trace in range(len(figure2["data"])):
    figure2_traces.append(figure2["data"][trace])

#Create a 1x2 subplot
this_figure = sp.make_subplots(rows=1, cols=2) 

# Get the Express fig broken down as traces and add the traces to the proper plot within in the subplot
for traces in figure1_traces:
    this_figure.append_trace(traces, row=1, col=1)
for traces in figure2_traces:
    this_figure.append_trace(traces, row=1, col=2)

#the subplot as shown in the above image
final_graph = dcc.Graph(figure=this_figure)

Output: