Attempting to use choropleth maps in folium for first time, index error - python-3.x

Question

This is my first time posting to stackoverflow, so I hope I am doing this correctly. I am currently finishing up a 'jumpstart' introduction to data analytics. We are utilizing Python with a few different packages, such as pandas, seaborn, folium etc. For part of our final project/presentation, I am trying to make a zipcode choropleth map. I have successfully imported folium and have my map displayed - the choropleth concept is new to me and is completely extracurricular. Trying to challenge myself to succeed.
I found an example of creating a choropleth map here that I am trying to use: https://medium.com/#saidakbarp/interactive-map-visualization-with-folium-in-python-2e95544d8d9b. I believe I correctly substituted the different object names for the data frame and map name that I am working with. For the geoJSON data, I found this https://github.com/OpenDataDE/State-zip-code-GeoJSON. I opened the geoJSON file in Atom, and found the feature title for what I believe to be the five digit zipcode 'ZCTA5CE10'.
Here is my code:
folium.Choropleth(geo_data='../data/tn_tennessee_zip_codes_geo.min.json',
data=slow_to_resolve,
columns=['zipcode'],
key_on='feature.properties.ZCTA5CE10',
fill_color='BuPu', fill_opacity=0.7, line_opacity=0.2,
legend_name='Zipcode').add_to(nash_map)
folium.LayerControl().add_to(nash_map)
nash_map
When I try to run the code, I get this error:
---------------------------------------------------------------------------
IndexError Traceback (most recent call last)
<ipython-input-114-a2968de30f1b> in <module>
----> 1 folium.Choropleth(geo_data='../data/tn_tennessee_zip_codes_geo.min.json',
2 data=slow_to_resolve,
3 columns=['zipcode'],
4 key_on='feature.properties.ZCTA5CE10',
5 fill_color='BuPu', fill_opacity=0.7, line_opacity=0.2,
~\anaconda3\lib\site-packages\folium\features.py in __init__(self, geo_data, data, columns, key_on, bins, fill_color, nan_fill_color, fill_opacity, nan_fill_opacity, line_color, line_weight, line_opacity, name, legend_name, overlay, control, show, topojson, smooth_factor, highlight, **kwargs)
1198 if hasattr(data, 'set_index'):
1199 # This is a pd.DataFrame
-> 1200 color_data = data.set_index(columns[0])[columns[1]].to_dict()
1201 elif hasattr(data, 'to_dict'):
1202 # This is a pd.Series
IndexError: list index out of range
Prior to this error, I had two columns from my dataframe specified, but I got some 'isnan' error that I am pretty sure was attributed to string type data in the second column, so I removed it. Now currently trying to figure out this posted error.
Can someone point me in the right direction? Please keep in mind that aside from this three week jumpstart program, I have zero programming knowledge or experience - so I am still learning terminology and concepts.
Thank you!

Answer 1

The error you got was an IndexError: list index out of range because you provided to the columns parameter with just one column columns=['zipcode']. It has to be two like this: columns=['zipcode', 'columnName_to_color_map'].
Where the first column 'zipcode' must match the object node in the GeoJSON file data (note the format/type must also match, that is string: '11372' IS NOT integer: 11372). The second column 'columnName_to_color_map' or whatever name you used should be the column which defined the choropleth colors.
Also note that key_on should match the first column 'zipcode'.
So the code should look like this:-
folium.Choropleth(geo_data='../data/tn_tennessee_zip_codes_geo.min.json',
data=slow_to_resolve,
columns=['zipcode', 'columnName_to_color_map'],
key_on='feature.properties.ZCTA5CE10',
fill_color='BuPu', fill_opacity=0.7, line_opacity=0.2,
legend_name='Zipcode').add_to(nash_map)
folium.LayerControl().add_to(nash_map)
nash_map