update answer format

app.py

@@ -8,13 +8,30 @@ from langchain_core.messages import HumanMessage
 
 import re
 
+import re
+
 def extract_answer(text: str) -> str:
-    # Try extracting after "FINAL ANSWER:" or similar patterns
-    match = re.search(r"FINAL ANSWER:\s*(.+)", text, re.IGNORECASE)
-    if match:
-        return match.group(1).strip()
-    # Otherwise, fall back to the whole text (assuming it's already clean)
-    return text.strip()
+    """
+    Clean and extract the final answer from agent output.
+    - Removes 'FINAL ANSWER:' if present.
+    - Strips trailing punctuation and whitespace.
+    - Normalizes comma/semicolon-separated lists.
+    """
+    # 提取 FINAL ANSWER 后的内容（如果存在）
+    match = re.search(r"final answer[:：]?\s*(.+)", text, re.IGNORECASE)
+    answer = match.group(1) if match else text
+
+    # 去除结尾句号和首尾空格
+    answer = answer.strip().rstrip('.').strip()
+
+    # 多项答案的格式标准化（如 a , b -> a,b）
+    if ',' in answer:
+        answer = ",".join(part.strip() for part in answer.split(','))
+    if ';' in answer:
+        answer = "; ".join(part.strip() for part in answer.split(';'))
+
+    return answer
+
 
 # --- Constants ---
 DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
@@ -33,14 +50,16 @@ class BasicAgent:
             outputs = result["messages"]
             for m in reversed(outputs):
                 if m.type == "ai":
-                    clean_answer = extract_answer(m.content)
-                    print(f"Extracted clean answer: {clean_answer}")
-                    return clean_answer
-            return "No answer found."
+                    raw_answer = m.content
+                    clean = extract_answer(raw_answer)
+                    print(f"Extracted clean answer: {clean}")
+                    return clean
+            return ""
         except Exception as e:
             print(f"LangGraph Agent error: {e}")
             return f"Error: {str(e)}"
 
+
 def run_and_submit_all(username: str):
     if not username:
         return "❌ Please enter your Hugging Face username.", None