update app for null

app.py

@@ -72,6 +72,8 @@ st.header("Data analysis by Chatbot")
 
 uploaded_file = st.file_uploader("Upload a CSV file", type=["csv"], key="uploaded_file")
 
+string_list =[]
+
 if uploaded_file is not None:
     # Display the uploaded file
     # st.write("Uploaded CSV file:", uploaded_file.name)
@@ -86,6 +88,8 @@ if uploaded_file is not None:
     # Convert each object-type column to a Python list
     lists_of_columns = [df[column].tolist() for column in object_columns.columns]
     string_of_csv = [element for sublist in lists_of_columns for element in sublist]
+    for element in string_of_csv:
+        string_list.append(str(element))
     
     
     df = df.applymap(lambda x: x.lower() if isinstance(x, str) else x)
@@ -96,10 +100,11 @@ if uploaded_file is not None:
     # df.columns = df.columns.map(lambda x: re.sub(pattern, '', x))
     df.columns = df.columns.astype(str)
     df.columns = df.columns.str.strip()
+    
 
 question = st.text_input("Ask your Question :", key="user_input")
 # Display suggestions dynamically
-suggestions = suggest_words(question.strip(), string_of_csv)
+suggestions = suggest_words(question.strip(), string_list)
 st.subheader("Suggestions:")
 if suggestions:
     for suggestion in suggestions: