add link customdata and hovertemplate

Author: nicolaskruchten

doc/python/sankey-diagram.md

@@ -6,7 +6,7 @@ jupyter:
       extension: .md
       format_name: markdown
       format_version: '1.2'
-      jupytext_version: 1.3.0
+      jupytext_version: 1.3.1
   kernel_info:
     name: python2
   kernelspec:
@@ -22,7 +22,7 @@ jupyter:
     name: python
     nbconvert_exporter: python
     pygments_lexer: ipython3
-    version: 3.7.3
+    version: 3.6.8
   plotly:
     description: How to make Sankey Diagrams in Python with Plotly.
     display_as: basic
@@ -158,13 +158,17 @@ fig = go.Figure(data=[go.Sankey(
       label = ["A1", "A2", "B1", "B2", "C1", "C2"],
       customdata = ["Long name A1", "Long name A2", "Long name B1", "Long name B2",
                     "Long name C1", "Long name C2"],
-      hovertemplate='%{customdata} <br> %{value} <extra></extra>',  
+      hovertemplate='Node %{customdata} has total value %{value}<extra></extra>',  
       color = "blue"
     ),
     link = dict(
       source = [0, 1, 0, 2, 3, 3], # indices correspond to labels, eg A1, A2, A2, B1, ...
       target = [2, 3, 3, 4, 4, 5],
-      value = [8, 4, 2, 8, 4, 2]
+      value = [8, 4, 2, 8, 4, 2],
+      customdata = ["q","r","s","t","u","v"],
+      hovertemplate='Link from node %{source.customdata}<br />'+
+        'to node%{target.customdata}<br />has value %{value}'+
+        '<br />and data %{customdata}<extra></extra>',  
   ))])
 
 fig.update_layout(title_text="Basic Sankey Diagram", font_size=10)