Plotly: How to draw a sankey diagram from a dataframe?

Question

I have a dataframe:

Vendor Name                 Category                    Count
AKJ Education               Books                       846888
AKJ Education               Computers & Tablets         1045
Amazon                      Books                       1294423
Amazon                      Computers & Tablets         42165
Amazon                      Other                       415
Flipkart                    Books                       1023

I am trying to draw a sankey diagram using the above dataframe, with the source being Vendor Name and target being Category, and the flow or width being the Count. I tried using Plotly, but no sucess. Does anyone has a solution with Plotly for making a Sankey Diagram?

Thanks

Answer 1

The answer to the post How to define the structure of a sankey diagram using a dataframe? will show you that forcing your Sankey data sources into one dataframe may quickly lead to confusion. You'll be better off separating nodes from links since they are constructed differently.

So your node dataframe should look something like this:

ID               Label    Color
0        AKJ Education  #4994CE
1               Amazon  #8A5988
2             Flipkart  #449E9E
3                Books  #7FC241
4  Computers & tablets  #D3D3D3
5                Other  #4994CE

And your links dataframe should look like this:

Source  Target      Value      Link Color
0       3          846888      rgba(127, 194, 65, 0.2)
0       4            1045      rgba(127, 194, 65, 0.2)
1       3         1294423      rgba(211, 211, 211, 0.5)
1       4           42165      rgba(211, 211, 211, 0.5)
1       5             415      rgba(211, 211, 211, 0.5)
2       5               1      rgba(253, 227, 212, 1)

Now, if you use a similar setup to the Scottish referendum diagram on plot.ly, youll be able to build this:

That particular diagram looks a bit odd because of the huge difference between the numbers. For illustrative purposes, I've replaced all your numbers with 1:

Here's the whole thing for an easy copy&paste into a Jupyter Notebook:

# imports
import pandas as pd
import numpy as np
import plotly.graph_objs as go
from plotly.offline import download_plotlyjs, init_notebook_mode, plot, iplot
init_notebook_mode(connected=True)

# Nodes & links
nodes = [['ID', 'Label', 'Color'],
        [0,'AKJ Education','#4994CE'],
        [1,'Amazon','#8A5988'],
        [2,'Flipkart','#449E9E'],
        [3,'Books','#7FC241'],
        [4,'Computers & tablets','#D3D3D3'],
        [5,'Other','#4994CE'],]

# links with your data
links = [['Source','Target','Value','Link Color'],

        # AKJ
        [0,3,1,'rgba(127, 194, 65, 0.2)'],
        [0,4,1,'rgba(127, 194, 65, 0.2)'],

        # Amazon
        [1,3,1,'rgba(211, 211, 211, 0.5)'],
        [1,4,1,'rgba(211, 211, 211, 0.5)'],
        [1,5,1,'rgba(211, 211, 211, 0.5)'],

        # Flipkart
        [2,5,1,'rgba(253, 227, 212, 1)'],
        [2,3,1,'rgba(253, 227, 212, 1)'],]

# links with some data for illustrative purposes ################
#links = [
#    ['Source','Target','Value','Link Color'],
#    
#    # AKJ
#    [0,3,846888,'rgba(127, 194, 65, 0.2)'],
#    [0,4,1045,'rgba(127, 194, 65, 0.2)'],
#    
#    # Amazon
#    [1,3,1294423,'rgba(211, 211, 211, 0.5)'],
#    [1,4,42165,'rgba(211, 211, 211, 0.5)'],
#    [1,5,415,'rgba(211, 211, 211, 0.5)'],
#    
#    # Flipkart
#    [2,5,1,'rgba(253, 227, 212, 1)'],]
#################################################################


# Retrieve headers and build dataframes
nodes_headers = nodes.pop(0)
links_headers = links.pop(0)
df_nodes = pd.DataFrame(nodes, columns = nodes_headers)
df_links = pd.DataFrame(links, columns = links_headers)

# Sankey plot setup
data_trace = dict(
    type='sankey',
    domain = dict(
      x =  [0,1],
      y =  [0,1]
    ),
    orientation = "h",
    valueformat = ".0f",
    node = dict(
      pad = 10,
    # thickness = 30,
      line = dict(
        color = "black",
        width = 0
      ),
      label =  df_nodes['Label'].dropna(axis=0, how='any'),
      color = df_nodes['Color']
    ),
    link = dict(
      source = df_links['Source'].dropna(axis=0, how='any'),
      target = df_links['Target'].dropna(axis=0, how='any'),
      value = df_links['Value'].dropna(axis=0, how='any'),
      color = df_links['Link Color'].dropna(axis=0, how='any'),
  )
)

layout = dict(
        title = "Draw Sankey Diagram from dataframes",
    height = 772,
    font = dict(
      size = 10),)

fig = dict(data=[data_trace], layout=layout)
iplot(fig, validate=False)