add full reference for np.array to extract scalar

Author: mmcky

.gitignore

@@ -5,6 +5,7 @@ dask-worker-space
 
 .vscode/
 .ipynb_checkpoints/
+.virtual_documents/
 
 lectures/mathfoo.py
 lectures/mod.py

lectures/numpy.md

@@ -709,7 +709,7 @@ row, column = a.shape
 result = np.empty((3, 3))
 for i in range(row):
     for j in range(column):
-        result[i, j] = a[i, j] + b[i]
+        result[i, j] = a[i, j] + b[i,0]
 
 result
 ```