add sankey tutorial

README.md

@@ -10,8 +10,9 @@ I am planning to share how to make publication-quality figures in python, I will
 4. [Tutorial IV (Violin plot, dendrogram)](https://towardsdatascience.com/making-publication-quality-figures-in-python-part-iv-violin-plot-and-dendrogram-ed0bb8b23ddd)
 5. [Tutorial V (Seaborn)](https://frankligy.medium.com/all-you-need-to-know-about-seaborn-6678a02f31ff)
 
-## Phase II: Plotly meets scientific figures
+## Phase II: Advanced tutorials
 1. [Plotly, interactive network](https://frankligy.medium.com/plotly-meets-scientific-visualization-8c2074f032cb)
+2. [Sankey plot strategies](https://frankligy.medium.com/the-essence-of-drawing-sankey-plot-491fb2cb234)
 
 
 ## Do you want to know some tricks?
@@ -21,5 +22,4 @@ I am planning to share how to make publication-quality figures in python, I will
 4. [legend,flexibly adjust it](https://github.com/frankligy/python_visualization_tutorial/blob/main/examples/legend.ipynb)
 5. [transformation, bbox](https://github.com/frankligy/python_visualization_tutorial/blob/main/examples/extend_ax.ipynb)
 6. [stacked legend](https://github.com/frankligy/python_visualization_tutorial/blob/main/examples/stacked_legends.ipynb)
-7. [markersize and difference between unit "unit" and "pixel"](https://github.com/frankligy/python_visualization_tutorial/blob/main/examples/markersize.ipynb) 
-8. stay tuned
+7. stay tuned

sankey/Sankey_tutorial.py

@@ -0,0 +1,45 @@
+
+import pandas as pd
+import matplotlib.pyplot as plt
+import numpy as np
+from matplotlib.path import Path
+from matplotlib.patches import PathPatch, Rectangle
+
+# draw the canvas and ax
+fig,ax = plt.subplots()
+ax.set_xlim([0,1])
+ax.set_ylim([0,1])
+ax.grid()
+
+# draw the recs
+rec_left = Rectangle(xy=(0.1,0.6),width=0.2,height=0.2,facecolor='orange',edgecolor='k')
+ax.add_patch(rec_left)
+rec_right = Rectangle(xy=(0.7,0.2),width=0.2,height=0.2,facecolor='green',edgecolor='k')
+ax.add_patch(rec_right)
+
+# demo the path object logics
+verts = [(0.3,0.8),(0.5,0.8),(0.7,0.4),(0.3,0.6),(0.3,0.8)]
+codes = [Path.MOVETO, Path.LINETO, Path.LINETO, Path.LINETO, Path.CLOSEPOLY]
+p = Path(verts,codes)
+ax.add_patch(PathPatch(p,fc='none'))
+
+# method1, Path, demo the curve4 logics
+verts = [(0.3,0.8), (0.5,0.8), (0.5,0.4), (0.7,0.4)]
+codes = [Path.MOVETO, Path.CURVE4, Path.CURVE4, Path.CURVE4]
+p = Path(verts,codes)
+ax.add_patch(PathPatch(p,fc='none',alpha=0.6))
+
+# method1, path
+verts = [(0.3,0.8), (0.5,0.8), (0.5,0.4), (0.7,0.4), (0.7,0.2), (0.5,0.2), (0.5,0.6), (0.3,0.6), (0.3,0.8)]
+codes = [Path.MOVETO, Path.CURVE4, Path.CURVE4, Path.CURVE4, Path.LINETO, Path.CURVE4, Path.CURVE4, Path.CURVE4, Path.CLOSEPOLY]
+p = Path(verts,codes)
+ax.add_patch(PathPatch(p,fc='red',alpha=0.6))
+
+# method2, convolve
+yu = np.array(50*[0.8] + 50*[0.4])
+yu_c = np.convolve(yu, 0.05*np.ones(20),mode='valid')
+yu_cc = np.convolve(yu_c, 0.05*np.ones(20),mode='valid')
+yd = np.array(50*[0.6] + 50*[0.2])
+yd_c = np.convolve(yd, 0.05*np.ones(20),mode='valid')
+yd_cc = np.convolve(yd_c, 0.05*np.ones(20),mode='valid')
+ax.fill_between(np.linspace(0.3,0.7,62),yd_cc,yu_cc,color='blue',alpha=0.6)