Python – Function to make a Plotly Scattermapbox with multiple trajectories failed, Plotly, List Comprehension

I’m trying to create the data plotly property using list understanding Scattermapbox

This is df:

import plotly.plotly as py
import plotly.graph_objs as go
import pandas as pd

df = pd. DataFrame(
    {"BOROUGH": ['MANHATTAN','MANHATTAN','MANHATTAN','QUEENS', 'QUEENS', 'QUEENS'],
     "CALL_QTY":[100, 10, 5, 15, 30, 45],
     "lat":[40.75, 40.72, 40.73, 40.72, 70.71, 40.721],
     "lng":[-73.99, -73.98, -70.97, -73.74, -73.73, -73.72]})

This is the tuple I’m going to iterate over :

u_sel = [list(a) for a in zip(['MANHATTAN', 'QUEENS'], # names
                              ['blue', 'orange'],      # colors
                              [0.6, 0.7])]             # opacity

This is the function I created to understand using a list:

def scattermap_data(df, u_sel):
    return([go. Scattermapbox(
        lat = df.loc[df['BOROUGH']==b].lat.astype('object'),
        lon = df.loc[df['BOROUGH']==b].lng.astype('object'),
        mode = 'markers',
        marker = dict(
            size=df.loc[df['BOROUGH']==b]. CALL_QTY,
            sizeref=0.9,
            sizemode='area',
            color=color,
            opacity=opacity
        )
    )] for b, color, opacity in u_sel
    )

Question: When I try to run the following command:

data = scattermap_data(df, u_sel)
layout = go. Layout(autosize=False,
                   mapbox= dict(
                       accesstoken=mapbox_access_token,
                       zoom=10,
                       style = 'dark',
                       center= dict(
                           lat=40.721319,
                           lon=-73.987130)
                   ),
                   title = "O God, Why?")
fig = dict(data=data, layout=layout)
py.iplot(fig, filename='tmapbox')

ValueError:
Invalid value of type 'builtins.generator' received for the 'data' property of
Received value: <generator object scattermap_data.<locals>.<genexpr> at 0x000000000A72AF68>

My question: I have the impression that this single df will be broken down into two scattermapbox tracked elements of the element – the structure of data, which would look like this:

data = [trace1, trace2]

(This looks similar in format to many plotly examples, where the trace list forms the fig parameter of dict in data.)

If I am interested in go. Scattermapbox does two separate traces, so this example does work, but I have several blocks that require this multi-tracking property, and I don’t want to repeat the code for each block (i.e. make 2 different trace instances for each block). I feel like I’m close to getting it to work, but I just need a few tweaks.

Auxiliary information: Plotly v. 3.3.0, python 3.6, I’m new to list understanding and plotly, thanks a lot for any help.

EDIT: Added import declaration to prevent hindering anyone.
edit2: Improved problem statement, title

I

figured out my question: I should use list() instead of square brackets in the return value of the function.

def scattermap_data(df, u_sel):
    return(list(go. Scattermapbox(
        lat = df.loc[df['BOROUGH']==b].lat.astype('object'),
        lon = df.loc[df['BOROUGH']==b].lng.astype('object'),
        mode = 'markers',
        marker = dict(
            size=df.loc[df['BOROUGH']==b]. CALL_QTY,
            sizeref=0.9,
            sizemode='area',
            color=color,
            opacity=opacity
        )
    ) for b, color, opacity in u_sel)
)