Update app.py

app.py

@@ -3,9 +3,10 @@ import matplotlib.pyplot as plt
 import networkx as nx
 
 # Add a sidebar with options
-sidebar_option = st.sidebar.radio("Select an option", ["Select an option", "Basic: Properties"])
+sidebar_option = st.sidebar.radio("Select an option", 
+                                 ["Select an option", "Basic: Properties", "Basic: Read and write graphs"])
 
-# Function to display properties and graph
+# Function to display properties and graph for Basic: Properties
 def display_graph_properties(G):
     # Initialize a list for path lengths
     pathlengths = []
@@ -50,25 +51,64 @@ def display_graph_properties(G):
     nx.draw(G, pos=pos, with_labels=True, node_color='lightblue', node_size=500, font_size=10, font_weight='bold')
     st.pyplot(plt)
 
-# Only display Basic: Properties when it is selected from the sidebar
+# Function to display graph for Basic: Read and write graphs
+def display_read_write_graph(G):
+    # Print the adjacency list of the graph
+    st.write("### Adjacency List:")
+    for line in nx.generate_adjlist(G):
+        st.write(line)
+    
+    # Write the graph's edge list to a file
+    st.write("### Writing Edge List to 'grid.edgelist' file:")
+    nx.write_edgelist(G, path="grid.edgelist", delimiter=":")
+    st.write("Edge list written to 'grid.edgelist'")
+
+    # Read the graph from the edge list
+    st.write("### Reading Edge List from 'grid.edgelist' file:")
+    H = nx.read_edgelist(path="grid.edgelist", delimiter=":")
+    st.write("Edge list read into graph H")
+
+    # Visualize the graph
+    st.write("### Graph Visualization:")
+    pos = nx.spring_layout(H, seed=200)  # Seed for reproducibility
+    plt.figure(figsize=(8, 6))
+    nx.draw(H, pos, with_labels=True, node_color='lightblue', node_size=500, font_size=10, font_weight='bold')
+    st.pyplot(plt)
+
+# Display Basic: Properties if selected
 if sidebar_option == "Basic: Properties":
-    # Set the title for the page
     st.title("Basic: Properties")
-
-    # Add a radio button for selecting the graph type
     option = st.radio("Choose a graph type:", ("Default Example", "Create your own"))
 
-    # Default example
+    # Default example: 5x5 grid graph
     if option == "Default Example":
         G = nx.lollipop_graph(4, 6)
         display_graph_properties(G)
 
     # Create your own graph
     elif option == "Create your own":
-        # Let the user input number of nodes and edges
         num_nodes = st.number_input("Number of nodes:", min_value=2, max_value=50, value=5)
         num_edges = st.number_input("Number of edges per group (for lollipop graph):", min_value=1, max_value=10, value=3)
 
         if num_nodes >= 2 and num_edges >= 1:
-            G = nx.lollipop_graph(num_nodes, num_edges)
-            display_graph_properties(G)
+            G_custom = nx.lollipop_graph(num_nodes, num_edges)
+            display_graph_properties(G_custom)
+
+# Display Basic: Read and write graphs if selected
+elif sidebar_option == "Basic: Read and write graphs":
+    st.title("Basic: Read and write graphs")
+    option = st.radio("Choose a graph type:", ("Default Example", "Create your own"))
+
+    # Default example: 5x5 grid graph
+    if option == "Default Example":
+        G = nx.grid_2d_graph(5, 5)  # 5x5 grid
+        display_read_write_graph(G)
+
+    # Create your own graph
+    elif option == "Create your own":
+        rows = st.number_input("Number of rows:", min_value=2, max_value=20, value=5)
+        cols = st.number_input("Number of columns:", min_value=2, max_value=20, value=5)
+
+        if rows >= 2 and cols >= 2:
+            G_custom = nx.grid_2d_graph(rows, cols)
+            display_read_write_graph(G_custom)